Smartwatches / Compare

Apple Watch Series 8 vs Fitbit Sense 2

A

Product A: Apple

Watch Series 8

88 of 150 known

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B

Product B: Fitbit

Sense 2

105 of 150 known

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Every value links to where we found it.

Only differences

AApple Watch Series 8

BFitbit Sense 2

General

7 of 10 differ

Series

Apple Watch1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker names the product Apple Watch Series 8 in the Apple Watch line.

Sense4Press releaseblog.google/products-and-platforms/devices/fitbit/versa-4-sense-2Read 23 October 2026Fitbit names the product Sense 2 in its Sense line and calls it its most advanced health-focused smartwatch.

Model numbersiMaker identifiers for this exact model and its listed variants. Excludes sibling models and other generations.

A2770, A2771, A2772, A2773, A2774, A27752Maker product pagesupport.apple.com/en-us/108056Read 10 October 2026Identify your Apple Watch: Series 8 GPS 41 mm A2770 and 45 mm A2771. GPS + Cellular aluminum and stainless steel 41 mm A2772 North America, A2773 Europe and Asia Pacific, A2857 China mainland. 45 mm A2774 North America, A2775 Europe and Asia Pacific, A2858 China mainland. China mainland A2857 and A2858 are excluded.

FB521, FB521BKGB-US, FB521SRWT-US, FB521GLBM-US1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Regulatory notices name Model FB521 with FCC ID XRAFB521. The retail colour model numbers come from the Abt listings.19Retailer pageabt.com/Fitbit-Sense-2-Graphite-Aluminum-Shadow-Grey-Strap-Advanced-Health-Fitness-Smartwatch-24mm-FB521BKGBUS/p/182315.htmlRead 23 October 2026Abt lists manufacturer model FB521BKGB-US. FB521SRWT-US and FB521GLBM-US are on the sister Abt listings. FB521 is the model in the manual.

GTIN / EAN

Not available

810073611429, 810073611443, 81007361143619Retailer pageabt.com/Fitbit-Sense-2-Graphite-Aluminum-Shadow-Grey-Strap-Advanced-Health-Fitness-Smartwatch-24mm-FB521BKGBUS/p/182315.htmlRead 23 October 2026Abt lists FB521BKGB-US with UPC 810073611429 (Graphite Aluminum with Shadow Grey band).

AnnouncediThe maker's first announcement of this model. This is separate from first retail availability.

7 September 20223Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Maker press release dated September 7, 2022.

24 August 20224Press releaseblog.google/products-and-platforms/devices/fitbit/versa-4-sense-2Read 23 October 2026Blog post dated Aug 24, 2022. Pre-orders started that day with worldwide availability that fall.

Status

Discontinued14Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 2026Discontinued Date: September 12, 2023, when Series 9 replaced it.

Available2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026The Google Store sells Sense 2 at 249.95 USD on the access date. That is a current price, not the launch price.

PredecessoriThe model this one directly replaced, in the same line, tier and size, as the maker or a trusted review names it.

Not available

Not available

SuccessoriThe model that directly replaced this one, in the same line, tier and size. A revision such as a Slim or OLED model does not count when a next generation exists.

Apple Watch Series 917Press articlemacrumors.com/guide/apple-watch-series-8-vs-series-9Read 23 October 2026MacRumors says the Apple Watch Series 9 replaces the Apple Watch Series 8 in Apple's lineup.

Not available

Launch price (US)iThe maker's US launch MSRP for the stated configuration, excluding tax. Current store prices and later discounts do not qualify.

From $3991Maker product pagesupport.apple.com/en-us/111848Read 10 October 20262Maker product pagesupport.apple.com/en-us/108056Read 10 October 20263Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 20264Press releaseapple.com/de/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 20266Maker product pageapple.com/watch/cellularRead 10 October 202614Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 202615Spec databasegsmarena.com/apple_watch_series_8_aluminum-11864.phpRead 10 October 202616Press articlet3.com/news/apple-watch-series-8-and-ultra-battery-size-discoveredRead 10 October 2026

$299.954Press releaseblog.google/products-and-platforms/devices/fitbit/versa-4-sense-2Read 23 October 2026Versa 4 is available for $229.95 and Sense 2 is available for $299.95 (USD). US prices exclude sales tax.

Launch price (EU)iThe maker's euro launch price for the stated configuration, including VAT as published. Current store prices and later discounts do not qualify.

From €4991Maker product pagesupport.apple.com/en-us/111848Read 10 October 20262Maker product pagesupport.apple.com/en-us/108056Read 10 October 20263Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 20264Press releaseapple.com/de/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 20266Maker product pageapple.com/watch/cellularRead 10 October 202614Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 202615Spec databasegsmarena.com/apple_watch_series_8_aluminum-11864.phpRead 10 October 202616Press articlet3.com/news/apple-watch-series-8-and-ultra-battery-size-discoveredRead 10 October 2026

€299.9514Spec databasenextpit.de/smartwatches/google-fitbit-sense-2Read 23 October 2026UVP 299,95 EUR, marketed from September 2022.15Press articlepcwelt.de/article/1206707/fitbit-sense-2-vorgestellt-hier-finden-sie-alle-infos.htmlRead 23 October 2026PC-Welt (Germany) at the launch: Die Fitbit Sense 2 kostet 299,95 Euro. German prices include VAT. Tech Advisor states EUR 299.95, GBP 269.99 and USD 299.95.

MarketsiISO country or region codes where this exact model or variant is sold. A source page's language does not establish availability.

US, DE, AU, CA, FR, IN, JP, AE, GB3Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Customers in Australia, Canada, France, Germany, India, Japan, the UAE, the UK, the US and more than 40 other countries and regions could order. Only the named countries are stored.

US, GB, DE, AU2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026US, GB, DE and AU Google Stores offer the model with a Buy button. Current prices are not launch prices.

ColoursiThe maker's own colour names

Midnight, Starlight, Silver, (PRODUCT)RED, Graphite (PVD), Gold (PVD)1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Finishes list: aluminum Midnight, Starlight, Silver, (PRODUCT)RED. Stainless steel Graphite (PVD), Silver, Gold (PVD). Apple Watch Hermes finishes are a separate collaboration line and are not stored.3Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026

Shadow Grey / Graphite Aluminum, Lunar White / Platinum Aluminum, Blue Mist / Soft Gold Aluminum2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Colors: Shadow Grey / Graphite Aluminum, Lunar White / Platinum Aluminum, Blue Mist / Soft Gold Aluminum.

Segment

Smartwatch1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker category: Apple Watch Series, the mainstream smartwatch line. Not the Ultra or SE line.

Smartwatch2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Page title: Fitbit Sense 2 Smartwatch. The Aug 24, 2022 Fitbit blog calls it a health-focused smartwatch.

OS updates promisediYears of explicitly promised OS updates. A security-only support period does not establish an OS-upgrade promise.

Not available

Not available

Security updates untiliExact end date published for security-update support of this model. Do not calculate it from a stated number of years. A security-only period does not promise OS upgrades.

Not available

Not available

Case

4 of 8 differ

Case sizeiMarketed case-size options. The marketed size can differ from physical case height, such as ceramic editions. Base dimensions describe the smallest base-material case.

41, 45mm1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Marketed 41 mm and 45 mm cases. Each variant row repeats its own size.

Not available

Case shape

Rectangular14Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 2026Rounded-corner rectangular LTPO OLED screen in a rectangular aluminum case (352x430, 904 sq mm display area).

Rectangular14Spec databasenextpit.de/smartwatches/google-fitbit-sense-2Read 23 October 2026Gehäuseform: eckig (square).

Case materialiMaterial of the housing body, not just the bezel. Use Mixed when the maker describes a mixture of housing/frame materials. Read the published-material field for the parts and proportions.

Aluminium1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Aluminium1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Materials: the housing and buckle on Sense 2 are made of aluminum.14Spec databasenextpit.de/smartwatches/google-fitbit-sense-2Read 23 October 2026Gehäusematerial: Aluminium.

Case material (as published)

Aluminum1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker names Aluminum and Stainless Steel finishes. Base is the aluminum case. Stainless steel rows are separate and exist only as GPS + Cellular models.

Aluminum1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Materials: the housing is aluminum. The store names the finishes Graphite, Platinum and Soft Gold Aluminum.

BackiMaterial of the back of the smallest base-material case. Other materials or regional editions can differ. See source notes.

Ceramic and sapphire crystal1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker feature line: Ceramic and sapphire crystal back. Apple Watch Hermes models have a ceramic back with a Hermes logo.

Not available

Case dimensionsiPhysical case height, width and thickness. The source note states exclusions such as the heart-rate sensor protrusion.

Height41Width35Thickness10.7mm(1.6 × 1.4 × 0.4 in)1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker lists 41 mm as height 41, width 35, depth 10.7 and 45 mm as height 45, width 38, depth 10.7. Orientation kept as published. The page does not say whether the heart sensor bulge is included.

Height40.5Width40.5Thickness11.2mm(1.6 × 1.6 × 0.4 in)2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Dimensions and weight: length 40.5 mm, width 40.5 mm, height 11.2 mm. The page states no sensor exclusion. The same page states weight 37.64 g without saying whether the band is included, so no weight is stored.

Weight (case only)iWatch body without a strap. An unqualified published weight must not be assumed to exclude the strap.

31.9g(1.1 oz)1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker weights, case only with no band. 41 mm aluminum GPS 31.9 g, aluminum GPS + Cellular 32.2 g, stainless steel GPS + Cellular 42.3 g. 45 mm aluminum GPS 38.8 g, aluminum GPS + Cellular 39.1 g, stainless steel GPS + Cellular 51.5 g. The base value is the 41 mm aluminum GPS model.

Not available

Weight with strapiWatch with the stated strap attached. Strap material and case size belong in the source note. Reviewer measurements belong in measured fields.

Not available

Not available

Durability

3 of 8 differ

Water resistanceiStatic water-pressure rating in atmospheres. It is not a safe swimming or diving depth. Diving limits are listed separately.

5ATM1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker footnote 3 gives 50 meters under ISO 22810:2010. 50 m is 5 ATM. It is a pressure rating, not a dive depth.

5ATM2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Water resistance: water resistant to 50 m. The Google compare page states 5 ATM.9Maker product pagestore.google.com/gb/magazine/google_pixel_watch_compareRead 23 October 2026Maker comparison, Water and dust resistance row: Sense 2 5 ATM.

Water resistance standard

ISO 22810:20101Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker footnote 3: 50 meters under ISO 22810:2010, for shallow water such as swimming. Not for scuba diving or waterskiing.

IEC 605291Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026IP Rating, printed page 78: Model FB521 has a water resistance rating of IPX8 under IEC 60529, up to a depth of 50 meters. IEC 60529 covers ingress, so no ISO pressure standard is inferred.

Dust and water rating

IP6X1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker footnote 2: certified IP6X dust resistant.

IP6X, IPX81Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026IP Rating: IPX8 under IEC 60529 up to 50 m, and IP6X dust-tight. Stored as the two published codes.

Dive rating

Not available

Not available

Max dive depthiMaker-rated depth for the stated diving use, not a conversion from the water-resistance pressure rating.

Not available

Not available

MIL-STD-810iMaker claim that the watch was tested against specified MIL-STD-810 methods. It is not a guarantee for every military-standard test.

Not available

Not available

MIL-STD-810 tests

Not available

Not available

Operating temperatureiPublished operating range. Source notes identify on-wrist limits and other operating conditions. Storage or charging limits are excluded.

Min0Max35°C7Maker product pagesupport.apple.com/en-us/108766Read 10 October 2026Apple Watch Series and SE models work best in ambient temperatures between 0 and 35 degrees C (32 to 95 F). The storage range of -20 to 45 degrees C is not stored.

Min-10Max45°C1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Environmental conditions, printed page 63: operating temperature 14 to 113 F (-10 to 45 C). Non-operating and charging ranges (0 to 35 C) are not stored.

Display

9 of 14 differ

Display type

LTPO OLED1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

OLED2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Display: AMOLED display.

Display type (as published)

Always-On Retina LTPO OLED display1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Verbatim: Always-On Retina LTPO OLED display.

AMOLED2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Display: AMOLED display.

Screen sizeiPublished active display diagonal for a rectangular display, or diameter for a round display. Do not calculate it from pixels or display area.

Not available

1.58in(4 cm)12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Display size 1.58 inch. Notebookcheck and nextpit state the same. Fitbit publishes no diagonal.14Spec databasenextpit.de/smartwatches/google-fitbit-sense-2Read 23 October 2026Displaygröße: 1,58 Zoll.

Resolution

352 × 430px1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: 45 mm 396 by 484 pixels, 41 mm 352 by 430 pixels. Stored in the case orientation, width by height.

336 × 336px12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Display resolution 336 x 336 pixels. Notebookcheck states the same.

Pixel densityiPublished pixel density. A rectangular diagonal formula must not be applied to a round display.

326ppi15Spec databasegsmarena.com/apple_watch_series_8_aluminum-11864.phpRead 10 October 2026Display line: 484 x 396 pixels (~326 ppi density). Apple states no pixel density for Series 8. The same figure is Apple's published value for other Apple Watch screens. Stored as listed.

Not available

Display area

904mm²1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: 45 mm 1143 sq mm and 41 mm 904 sq mm display area.

Not available

Touchscreen

Yes14Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 2026All Series 8 devices are controlled with a Digital Crown with haptic feedback and a touch capable display.

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Navigate Sense 2: color AMOLED touchscreen display and 1 button.

Max refresh rateiHighest published display refresh rate in active operation.

Not available

60Hz18Measurementnotebookcheck.net/Fitbit-Sense-2-Smartwatch-review-Automatic-activity-recording.717608.0.htmlRead 23 October 2026Notebookcheck spec box lists 60 Hz. Fitbit publishes no refresh rate. Treated as a stated spec, not a measurement.

Min refresh rateiLowest published display refresh rate, usually in always-on mode. It is not the active-use minimum unless stated.

Not available

Not available

Peak brightnessiMaker peak-brightness claim. It may apply to a small area or bright ambient light. Full-screen limits and battery/temperature conditions belong in source notes.

1,000nits1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: up to 1000 nits brightness. Window size and ambient conditions are not stated. Not a reviewer measurement.

1,000nits12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Display brightness: Up to 1,000 nits. Fitbit publishes no nit figure in the documents read, so this is a spec database claim. Window size and ambient conditions are not stated.

Minimum brightness

Not available

Not available

Always-on display

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Adjust always-on display section. The setting reduces battery life.3Maker product pagestore.google.com/us/product/fitbit_sense_2Read 23 October 2026Always-on display mode: keeps your display on at all times (may require more frequent charging).

Display cover

Other glass1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Gorilla Glass2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Display: Corning Gorilla Glass 3.

Display cover (as published)

Ion-X glass1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker finish table: aluminum models have Ion-X glass, stainless steel models have sapphire crystal (from the Identify your Apple Watch page).

Corning Gorilla Glass 32Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Display: Corning Gorilla Glass 3.

Platform

11 of 15 differ

Platform

watchOS1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: Series 8 is powered by watchOS 9 (press release). The tech specs page lists no other platform.3Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026

Proprietary2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026No OS name is printed on the spec page. The Fitbit blog says the watch is powered by the new Fitbit OS, a proprietary platform with its own Gallery.

OS at launch

watchOS 93Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Maker: Series 8 is powered by watchOS 9.

Fitbit OS4Press releaseblog.google/products-and-platforms/devices/fitbit/versa-4-sense-2Read 23 October 2026Powered by the new Fitbit OS. No version number is published.

Software

Not available

Not available

Latest OS

watchOS 269Maker product pageapple.com/os/watchosRead 10 October 2026The watchOS 27 compatible-device list starts at Series 9 and does not include Series 8. The latest OS for Series 8 is watchOS 26. Checked on the access date.14Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 2026Maximum OS: watchOS 26.x. The Series 8 does not support watchOS 27 or later. watchOS 26 lacks the Wrist Flick gesture and Hypertension notifications on this model.

Fitbit OS, firmware 220.317Maker product pagesupport.google.com/googlehealth/answer/14236725Read 23 October 2026Fitbit firmware release notes: Sense 2 latest listed version 220.31 (bug fixes and improvements) on the access date. No Fitbit OS major version number is published.

Works with

iOS1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker compatibility line: requires an iPhone. No Android pairing.

iOS, Android2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Requirements: Apple iOS 16.4 or higher, Android OS 11.0 or higher, current on the access date.

Phone requirement

Launch: iPhone 8 or later with iOS 16. Current watchOS 26 requires iPhone 11 or later with iOS 26.1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker compatibility line: iPhone 8 or later with iOS 16 or later. The current watchOS 26 requirement comes from the EveryMac source.14Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 2026watchOS 9 requires iPhone 8 or later with iOS 16. watchOS 26 requires iPhone 11 or later with iOS 26.

Google Health app on a compatible device running Apple iOS 16.4 or higher or Android OS 11.0 or higher2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Requirements: the Google Health app on a device running Apple iOS 16.4 or higher or Android OS 11.0 or higher. This is the current requirement. The 2022 launch requirement may have been lower.

App store

Yes12Owner's manualsupport.apple.com/guide/watch/open-apps-apda1bf1a95b/26/watchos/26Read 10 October 2026Guide lists the App Store app for Apple Watch. Series 8 runs watchOS 26.

No1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026The Fitbit Gallery offers Fitbit apps and clock faces. Tom's Guide states third-party apps cannot be downloaded.17Reviewtomsguide.com/news/fitbit-sense-2Read 23 October 2026Review: you don't get access to third-party apps. You can download custom watch faces but not third-party apps. The Sense 2 and Versa 4 cannot.

Voice assistants

Not available

Amazon Alexa1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Voice Assistant: Amazon Alexa Built-in. Needs the phone app running in the background. Not available in all countries.3Maker product pagestore.google.com/us/product/fitbit_sense_2Read 23 October 2026Smarts and more: Alexa Built-in.

Chipset

Apple S8 SiP1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: S8 SiP with 64-bit dual-core processor.

Ambiq Apollo4 Plus12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Platform: Ambiq Apollo4 Plus, ARM Cortex-M4 at 96-192 MHz. Fitbit publishes no chip and Notebookcheck says it does not disclose the SiP. Ambiq's own presentation says Apollo4 powers the Sense product line, which supports the chip family but not the Plus suffix.16Press articleambiq.com/wp-content/uploads/2022/12/Key-to-the-Future-of-Electronics.pdfRead 23 October 2026Ambiq presentation: Apollo4 powers Inspire, Versa and Sense product lines of Fitbit, and Versa 4, Sense 2 and Inspire 3 were launched in August 2022.

Process

Not available

Not available

CPU cores

21Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

112Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Same Platform entry: one ARM Cortex-M4 core.

CPU configuration

AApple Watch Series 8

Not available

BFitbit Sense 2

Count	Core	Max clock (GHz)
1	Arm Cortex-M4	0.192

Source12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Same Platform entry: ARM Cortex-M4 at 96-192 MHz. 192 MHz is stored as the maximum.

Max CPU clock

Not available

0.192GHz=CalculatedFrom CPU configuration

GPU

Not available

Not available

Low-power coprocessor

Not available

Not available

Memory

2 of 2 differ

RAMiKeep published GB values as stated. Convert a source explicitly labelled MB using 1000 MB per GB and preserve its original figure and unit in the note. Do not assume MB means MiB. Convert explicit MiB or GiB to decimal GB through their byte definitions, recording the conversion in the note. This normalization does not establish an exact physical byte count.

1GB14Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 2026Onboard RAM: 1 GB. Apple does not publish RAM. GSMArena also lists 1GB RAM.

2.75 MB12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Same entry: 2.75 MB on-chip SRAM, stored as 0.00275 GB with 1000 MB per GB. No maker figure exists.

StorageiTotal built-in storage the maker states, in decimal GB. Space available to the user is lower and goes in the source note. A figure the maker gives only as available space is not stored.

32GB1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: Capacity 32GB. Not RAM.

4GB18Measurementnotebookcheck.net/Fitbit-Sense-2-Smartwatch-review-Automatic-activity-recording.717608.0.htmlRead 23 October 2026Performance and runtime: the manufacturer has installed 4 GB of internal storage, usable for apps and watch faces. Fitbit publishes no storage figure. Routes and music cannot be stored.

Health sensors

4 of 8 differ

Heart rate sensor

Third-generation optical heart sensor1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Multi-path optical heart rate sensor1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: multi-path optical heart rate tracker. The Google Store spells it Multi-path optical heart rate sensor.2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Sensors and components: multi-path optical heart rate sensor.

ECG capabilityiElectrical heart sensing hardware with an ECG capability. The ECG app can require an eligible country, age and paired phone.

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Electrical heart sensor with the ECG app. The app needs a supported country and a user aged 22 or older (footnote 5).

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: multipurpose electrical sensors compatible with the ECG app and EDA Scan app. The ECG app is not available in all countries.2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Sensors: multipurpose electrical sensors compatible with ECG app and EDA app. ECG not available in all countries.

Blood oxygen sensingiBlood-oxygen sensing capability. App availability and medical status vary by market.

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Blood oxygen sensor with the Blood Oxygen app. The app is for wellness and not medical use (footnote 4).

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: red and infrared sensors for oxygen saturation (SpO2) monitoring.

Skin temperature sensingiA sensor or supported function that measures skin temperature. It is not a core-body thermometer.

Yes3Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Maker: two-sensor wrist temperature sensing, one sensor on the back and one under the display. It samples during sleep and measures changes as small as 0.1 C. Not a medical device and not a core body thermometer.

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: on-wrist skin temperature sensor. Track your skin temperature changes: nightly variation from a personal baseline. Not available in all markets.

Blood pressure featureiPublished blood-pressure feature category. Hypertension notifications are not numerical blood-pressure readings.

None8Maker product pagesupport.apple.com/en-us/123002Read 10 October 2026watchOS 26 notes: hypertension notifications are available on Apple Watch Series 9 and later and Ultra 2 and later. Series 8 is not listed, and the watch has no blood pressure feature.

None12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Blood pressure: No. The maker sensor list and feature pages have no blood-pressure feature.

Body composition sensor

Not available

No1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026The complete sensor list in Sensors and Components has no bioelectrical impedance sensor.12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Body composition: No.

Skin conductance (EDA)

Not available

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: electrical sensor to measure skin conductance (cEDA) for stress detection. Manage stress: continuous EDA identifies body responses.4Press releaseblog.google/products-and-platforms/devices/fitbit/versa-4-sense-2Read 23 October 2026Sense 2 has a new Body Response sensor for continuous electrodermal activity (cEDA).

Medical clearancesiNamed regulatory clearances and their jurisdiction. General water resistance or an ECG sensor does not establish medical clearance.

FDA-cleared AFib History (US)3Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Maker states the AFib History feature is FDA-cleared. US jurisdiction. It is for people aged 22 or older diagnosed with AFib.

ECG app: FDA clearance, ECG app: EU clearance, Irregular Heart Rhythm Notifications: FDA clearance, Irregular Heart Rhythm Notifications: EU clearance3Maker product pagestore.google.com/us/product/fitbit_sense_2Read 23 October 2026Heart section: the ECG app assesses heart rhythm for atrial fibrillation. Clearance wording is in the Fitbit blog.5Press releaseblog.google/products-and-platforms/devices/fitbit/fitbit-sense-2-versa-4Read 23 October 2026Footnote and text: the ECG app on Sense 2 and the Irregular Heart Rhythm Notifications on both watches have FDA and EU clearance. Only in select countries, not for people under 22 or with known atrial fibrillation.

Motion and environment sensors

2 of 9 differ

Accelerometer

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: 3-axis accelerometer.2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Sensors and components: 3-axis accelerometer.

Accelerometer range

256G1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: high-g accelerometer, up to 256 g-forces with Fall Detection and Crash Detection.

Not available

Gyroscope

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: gyroscope.

Barometric altimeter

Yes15Spec databasegsmarena.com/apple_watch_series_8_aluminum-11864.phpRead 10 October 2026Sensors line lists accelerometer, gyro, heart rate, barometer, always-on altimeter, compass, SpO2, VO2max and temperature.

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: altimeter, which tracks altitude changes.

Compass

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

No1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026The complete sensor list in Sensors and Components has no compass or magnetometer. Gadgets & Wearables also lists Compass: No.12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Compass: No. Geomagnetic: No.

Ambient light sensor

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: ambient light sensor.

Depth gauge

Not available

Not available

Depth gauge rangeiPublished measurement range of the depth gauge, distinct from maximum diving depth and water-pressure resistance.

Not available

Not available

Water temperature sensor

Not available

Not available

Health and fitness

2 of 5 differ

Health featuresiSupported health functions with country, phone and subscription restrictions in the source notes. Upcoming functions are not counted as available.

Irregular rhythm notifications, AFib history, ECG app, Blood oxygen app, Sleep tracking, Sleep stages, Cycle tracking, Temperature-based ovulation1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker lists the ECG app, the Blood Oxygen app and irregular rhythm notification (footnote 5, not for people previously diagnosed with AFib). Country, age and iPhone limits apply.3Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Maker: temperature sensing with retrospective ovulation estimates and improved period predictions, Cycle Tracking, sleep stages in watchOS 9 (REM, Core, Deep from the accelerometer), and FDA-cleared AFib History. Sleep tracking is part of the same watchOS 9 sleep section.

Continuous heart rate, Heart rate alerts, Irregular rhythm notifications, ECG app, Blood oxygen app, Heart rate variability, Sleep tracking, Sleep stages, Stress tracking, Readiness score, Cycle tracking1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Today and sleep sections: sleep stages (REM, light, deep) and sleep score, stress management score, readiness score (Premium), menstrual health tile, high and low heart rate notifications after 10 inactive minutes, heart-rate variability under Advanced health metrics, oxygen saturation. Daily readiness score needs Fitbit Premium. Irregular rhythm notifications and the ECG app come from the Fitbit blog.3Maker product pagestore.google.com/us/product/fitbit_sense_2Read 23 October 2026Heart rate tracking, high and low heart rate notifications, irregular heart rhythm notifications, ECG app, HRV, breathing rate, SpO2, sleep tracking and sleep stages, Stress Management Score, Daily Readiness Score, menstrual health tracking. The Daily Readiness Score is a Premium feature in the manual.

Fitness featuresiSupported workout functions. A sport-profile name alone does not prove advanced metrics such as running power or running dynamics. Trackback follows the recorded route back to the start. A compass arrow that points straight to the start does not count.

VO2 max, Running dynamics, Pool swim, Open water swim, Trackback3Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Maker watchOS 9 section: running form metrics Stride Length, Ground Contact Time and Vertical Oscillation (running dynamics), Backtrack in the Compass app, and a Multisport workout for any sequence of swimming, biking or running. Heart Rate Zones, Custom Workouts, Pacer, Race Route, Segments and Splits have no matching option and are not stored. Swim use is also supported by the 50 m water-resistance statement on the tech specs page.13Maker spec sheet (PDF)apple.com/healthcare/docs/site/Using_Apple_Watch_to_Estimate_Cardio_Fitness_with_VO2_max.pdfRead 10 October 2026Apple white paper: with watchOS 7, Apple Watch Series 3 and later estimate VO2 max. Series 8 is a later model.

Automatic workout detection, VO2 max, Pool swim, Interval workouts, Turn-by-turn navigation1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Exercise settings list Pool Length, Interval, Auto Start and Auto-Stop. Track your exercise automatically (SmartTrack, 15 minute minimum). Google Maps gives turn-by-turn directions and needs the paired phone nearby with the app running. View your cardio fitness score (stored as vo2_max, see the Google Health VO2 max help page).3Maker product pagestore.google.com/us/product/fitbit_sense_2Read 23 October 2026Fitness features: Cardio Fitness Score estimated from VO2 max, SmartTrack Automatic Exercise Recognition (in app only), Google Maps turn-by-turn directions.11Maker product pagesupport.google.com/googlehealth/answer/14237924Read 23 October 2026Learn about your VO2 max: VO2 max, formerly the cardio fitness score, is estimated during outdoor runs with GPS. The Sense 2 manual names the cardio fitness score.

Sport profilesiPublished count of distinct sport/activity profiles. A claim such as 180+ is not an exact integer count.

Not available

Not available

Dive modesiActual supported dive modes. Water resistance or a depth app alone does not establish decompression-capable scuba support.

Not available

Not available

External sensorsiTypes of external workout sensors the watch can pair with. GPS reception, phone data and built-in sensors do not qualify.

Not available

Not available

Safety

4 of 6 differ

Fall detectioniAutomatic fall detection. Incident detection restricted to recorded workouts is not counted as general fall detection.

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 20263Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Maker: Series 8 builds on best-in-class safety features like the ECG app and fall detection.

No9Maker product pagestore.google.com/gb/magazine/google_pixel_watch_compareRead 23 October 2026Safety and emergency rows (Safety Check, Emergency Sharing, Medical information, Fall Detection, Emergency SOS, Emergency international calling, Car Crash Detection, Earthquake Alerts): the Sense 2 column is empty for all of them. No fall detection.

Car crash detection

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 20263Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Maker: new Crash Detection on Series 8 using a more powerful gyroscope and accelerometer. It dials emergency services after a 10-second countdown if the user is unresponsive.

No9Maker product pagestore.google.com/gb/magazine/google_pixel_watch_compareRead 23 October 2026Same Safety rows: Car Crash Detection is empty in the Sense 2 column.

Emergency SOSiA manual emergency alert to emergency services or preset contacts. Source notes identify the recipient, paired-phone requirement and country limits. Satellite is listed separately.

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker footnote 1: needs a cellular connection or Wi-Fi Calling from the watch or the nearby iPhone.

No9Maker product pagestore.google.com/gb/magazine/google_pixel_watch_compareRead 23 October 2026Same Safety rows: Emergency SOS is empty in the Sense 2 column.

Emergency sireniPublished or measured siren sound level in decibels. Audible distance alone does not establish this value. Measurement distance belongs in source notes.

Not available

Not available

Live location sharingiShares live location during supported use. A paired phone or data subscription may be required.

Not available

Not available

Dedicated LED flashlightiA dedicated hardware LED flashlight. Lighting the display white is not counted.

Not available

No9Maker product pagestore.google.com/gb/magazine/google_pixel_watch_compareRead 23 October 2026No flashlight appears in the Sense 2 sensor and component list. Gadgets & Wearables states Flashlight: No.12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Flashlight: No.

Positioning

3 of 3 differ

PositioningiPublished satellite systems and signal bands. Do not infer bands from dual-frequency support alone.

L1 GPS, GLONASS, Galileo, QZSS, BeiDou1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: L1 GPS, GLONASS, Galileo, QZSS and BeiDou.

GPS, GLONASS1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: built-in GPS receiver + GLONASS. Dynamic GPS can use the phone's GPS instead to save battery. No band or dual-frequency claim.4Press releaseblog.google/products-and-platforms/devices/fitbit/versa-4-sense-2Read 23 October 2026Built-in GPS is named for Sense 2.

Dual-band GNSSiMaker-stated dual-frequency satellite reception. Supported constellations and signal bands are listed separately.

No1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker lists L1 GPS only. No L5 or other second band is listed. Stored as false from the L1-only statement.

Not available

Offline mapsiMap data stored on the watch and usable without live phone data. GPX routes or breadcrumb tracks alone are not offline maps.

Not available

No12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Offline maps: No. The manual requires the phone and background app for Google Maps.

Connectivity

9 of 15 differ

BluetoothiPublished Bluetooth support for this model. The version is recorded separately. Unknown version does not mean the radio is absent.

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Wireless technology: Bluetooth 5.0 radio transceiver and NFC chip.

Bluetooth version

5.31Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: Bluetooth 5.3. EveryMac records that some early Apple documents wrongly said 5.0.

5.01Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Wireless technology, printed page 62: Bluetooth 5.0 radio transceiver and NFC chip.14Spec databasenextpit.de/smartwatches/google-fitbit-sense-2Read 23 October 2026Bluetooth: 5.

Wi-FiiPublished Wi-Fi support for this model. The standard and bands are recorded separately. Unknown standard does not mean Wi-Fi is absent.

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

No1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components: WiFi (deactivated, cannot be turned on). Stored as false because the user cannot use it. No Wi-Fi standard is stored.

Wi-Fi standard

Wi-Fi 41Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Not available

Wi-Fi bands

2.4 GHz, 5 GHz1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: 802.11b/g/n 2.4GHz and 5GHz. The standard is Wi-Fi 4 (802.11n).

Not available

CellulariTrue when a cellular edition is sold. A variant row states whether that individual model has cellular hardware.

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

No1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026No cellular radio is listed in Wireless technology (Bluetooth and NFC only).

Network

LTE1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker: LTE and UMTS on GPS + Cellular models. UMTS has no option in the schema, so only LTE is stored.

Not available

4G bandsiPublished LTE bands for the stated regional cellular model. Do not transfer bands to another region or Wi-Fi-only model.

Not available

Not available

5G bandsiPublished 5G NR bands for the stated regional cellular model. RedCap support does not establish conventional full-bandwidth phone 5G.

Not available

Not available

NFCiSome regions sell an NFC edition, so it is per variant.

Yes15Spec databasegsmarena.com/apple_watch_series_8_aluminum-11864.phpRead 10 October 2026NFC: Yes.

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Wireless technology: NFC chip. Contactless Payments section describes the built-in NFC chip.

Contactless payments

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker lists Apple Pay. Eligible cards, banks and regions required.

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Contactless Payments: set up Google Wallet in the Fitbit app and pay at contactless terminals.3Maker product pagestore.google.com/us/product/fitbit_sense_2Read 23 October 2026Smarts and more: Google Wallet, make purchases from your wrist everywhere Google Pay is accepted.

Payment services

Apple Pay1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026

Google Wallet1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Contactless Payments: Google Wallet. The text also names Fitbit Pay for the older service name.

Ultra-wideband

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker lists the U1 chip (Ultra Wideband). Availability varies by region (footnote 11).

No1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Wireless technology lists only a Bluetooth radio and an NFC chip. No UWB radio.

Satellite

Not available

None9Maker product pagestore.google.com/gb/magazine/google_pixel_watch_compareRead 23 October 2026No satellite feature in any Safety row. Published radios are Bluetooth and NFC. GPS reception is separate.

ANT+

Not available

Not available

Audio

2 of 4 differ

Speaker

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker feature list includes Speaker and Microphone.

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Sensors and Components lists Speaker and Microphone. The Google Store rates the speaker at 75 dB SPL at 10 cm. That is not an emergency siren.

Microphones

Not available

Not available

Calls on the watchiVoice-call capability of the marketed model, including sold cellular editions. Variant radio capability and paired-phone requirements still apply.

Cellular or phone6Maker product pageapple.com/watch/cellularRead 10 October 2026Cellular models with an active service plan make calls and send texts without the iPhone. Series 8 cellular models A2772 and A2774 (North America) and A2773 and A2775 are listed as compatible. GPS models need the paired iPhone or Wi-Fi calling.

Phone only1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Answer or reject phone calls and Take on-wrist phone calls: calls go through the paired iPhone or Android phone, which must be nearby with the Fitbit app running. No cellular model exists.

Music on the watchiPlays audio stored on the watch. Remote control of phone playback or streaming alone does not qualify.

Yes1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026The maker battery test uses music playback from Apple Watch via Bluetooth, so music is stored on the watch.

No12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026On-board music storage: No. Smartphone music control only.

Controls

4 of 5 differ

ButtonsiPhysical controls used to operate the watch, excluding the rotating crown and strap-release buttons. A clickable rotating crown is counted only in Crown.

110Owner's manualsupport.apple.com/guide/watch/use-buttons-and-gestures-apd1d9d7efca/26/watchos/26Read 10 October 2026Guide: you interact with Apple Watch using the Digital Crown, side button, Action button (Ultra models only) and gestures. Series 8 has one operating button, the Side button. The Digital Crown is in Crown.

11Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Navigate Sense 2: color AMOLED touchscreen display and 1 button.

Named operating buttonsiNames of operating buttons, excluding the crown and strap-release controls.

Side button10Owner's manualsupport.apple.com/guide/watch/use-buttons-and-gestures-apd1d9d7efca/26/watchos/26Read 10 October 2026Guide names the side button. The Action button is for Ultra models.

Button1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Navigate Sense 2: the single button opens the apps menu, returns to the clock face and has long-press and double-press shortcuts.

CrowniA crown that rotates to control the interface. A round push button that does not rotate is not a crown.

Rotating haptic14Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 2026Digital Crown with haptic feedback. It rotates, so it is in Crown and not in the button count.

None1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Navigate Sense 2 describes only the touchscreen and 1 button. No crown.

Rotating bezeliPhysical rotation or touch gestures around the display edge. A fixed decorative bezel is None.

Not available

None1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Navigate Sense 2 describes only the touchscreen and 1 button. No bezel control.

Gestures

Not available

Turn your wrist, Briefly cover the watch face with your opposite hand, Triple-tap the screen1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Screen wake setting: Button & motion turns the screen on when you turn your wrist. Turn off the screen: briefly cover the watch face with your opposite hand, except with always-on display. Screen Zoom: Magnify works on a triple-tap.

Battery and charging

9 of 13 differ

Battery capacityiPublished battery capacity for the stated case size. Rated and typical capacity are distinguished in source notes.

282 to 308mAh1Maker product pagesupport.apple.com/en-us/111848Read 10 October 20262Maker product pagesupport.apple.com/en-us/108056Read 10 October 20263Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 20264Press releaseapple.com/de/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 20266Maker product pageapple.com/watch/cellularRead 10 October 202614Spec databaseeverymac.com/systems/apple/apple-watch/specs/apple-watch-series-8-aluminum-gps-41mm.htmlRead 10 October 202615Spec databasegsmarena.com/apple_watch_series_8_aluminum-11864.phpRead 10 October 202616Press articlet3.com/news/apple-watch-series-8-and-ultra-battery-size-discoveredRead 10 October 2026

162mAh12Spec databasegadgetsandwearables.com/technical-specs/fitbit-sense-2Read 23 October 2026Battery: rechargeable lithium-polymer battery, 162 mAh.13Retailer pageifixit.com/products/fitbit-sense-2-batteryRead 23 October 2026iFixit replacement battery listing for Sense 2: 0.62 Wh, 3.87 V, 162 mAh. 162 mAh x 3.87 V = 0.627 Wh, which agrees. It is a parts listing, not a teardown. Gadgets & Wearables, Notebookcheck and nextpit also state 162 mAh. Two Argos listings print 260 mAh, which is not used.14Spec databasenextpit.de/smartwatches/google-fitbit-sense-2Read 23 October 2026Batteriekapazität (Netto): 162 mAh.

Claimed battery lifeiMaker endurance claims with distinct operating modes and case sizes. With solar describes augmentation of that estimate, not hardware capability. Use false for ordinary claims without solar augmentation, true for explicitly solar-aided claims, and omit it when solar qualification is unclear. Source notes state AOD, GNSS, music and solar conditions. Do not create a normal-use row from an AOD-only claim. Low power denotes the maker battery-saver mode. Keep its typical, light-use and always-on claims separate from standard-mode claims. GPS power saving identifies an intermediate reduced-accuracy GNSS saving preset. Source notes retain the maker's preset name and published conditions. Max battery GPS is the distinct maximum-saving claim. When the maker has only one GPS saving preset, it is GPS power saving.

AApple Watch Series 8

Mode	With solar	Hours (h)
Smartwatch	No	18
Low power	No	36

Source1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Up to 18 hours: 90 time checks, 90 notifications, 45 minutes of app use and a 60-minute workout with music playback from the watch via Bluetooth. GPS models stay connected to iPhone by Bluetooth. Cellular models use 4 h of LTE and 14 h of Bluetooth. Tested by Apple in August 2022 on preproduction units with prerelease software. Not an always-on-display-only claim. No solar assistance.3Press releaseapple.com/newsroom/2022/09/apple-reveals-apple-watch-series-8-and-the-new-apple-watch-seRead 10 October 2026Maker: Low Power Mode can extend battery life up to 36 hours for Series 8 with iPhone present. It limits the Always-On display and other sensors.

BFitbit Sense 2

Mode	With solar	Hours (h)
Smartwatch	No	144
Always-on	No	72
GPS	No	5

Source2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Battery and power: battery life of 6+ days, stored as 144 h as a minimum figure. Up to 5 hours with continuous GPS, stored as the gps row. The always-on display, SpO2 and cEDA sensor need more frequent charging. The Google Health support article states up to 12 hours with continuous GPS for Sense 2, a conflict. The model spec page is used because the Oct 2022 Fitbit.com page printed the same 5 hours.6Maker product pagesupport.google.com/googlehealth/answer/14226518Read 23 October 2026Estimated battery life table: Fitbit Sense 2 6+ days. Footnote: with always-on display, Sense 2 has a battery life of up to 3 days (stored as 72 h always_on). The same footnote says Sense 2 has up to 12 hours with continuous GPS, which conflicts with the 5 hours on the model spec page. The 12 hour figure is not stored.10Maker product pageweb.archive.org/web/20221022073607/https://www.fitbit.com/global/us/products/smartwatches/sense2Read 23 October 2026Archived Fitbit.com Sense 2 page, Oct 22, 2022: battery life of 6+ days and up to 5 hours with continuous GPS. Same wording as the current Google Store.

Smartwatch mode (claimed)iMaker normal-use smartwatch claim without solar. A watch with only an explicit AOD-mode claim has no value here. Workloads differ and source notes must be read.

18h=CalculatedFrom Claimed battery life

144h=CalculatedFrom Claimed battery life

AOD battery life (up to)iMaker claimed smartwatch endurance with the always-on display enabled and without solar, for the base case. Source notes preserve workload and case conditions. This is a claim, not a measured test or an AOD-off estimate.

Not available

72h=CalculatedFrom Claimed battery life

GPS mode (claimed)iMaker regular GPS/GNSS activity claim without solar, for the base case. AOD, multi-band, music and power-saving conditions have separate rows when published.

Not available

5h=CalculatedFrom Claimed battery life

Solar chargingiPublished solar charging hardware capability. An ordinary battery estimate without solar augmentation does not prove that the watch lacks solar charging hardware.

Not available

Not available

Charging methodiThe connection at the watch, not the cable end at the USB adapter. A proprietary inductive puck is not Qi unless interoperability is explicitly established.

Magnetic puck1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker lists a USB-C magnetic fast charging cable. Contact is a magnetic puck.

Magnetic pins1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Charge your watch: hold the cable end near the port on the back until it attaches magnetically. The pins on the cable align with the port on the back.

Charging guidanceiPublished charging requirements, nominal estimates and compatibility guidance. Keep adapter ratings separate from power accepted by the watch.

Not available

Not available

Max charging power (watch)iPublished maximum charging power at the watch. Adapter rating or charger input power does not prove the power accepted by the watch.

Not available

Not available

Fast chargingiAn explicit fast-charging capability claim. A short charging time or high adapter wattage alone does not qualify.

Yes5Maker product pagesupport.apple.com/en-us/102454Read 10 October 2026Fast charging is supported on Apple Watch Series 7 and later.

Yes5Press releaseblog.google/products-and-platforms/devices/fitbit/fitbit-sense-2-versa-4Read 23 October 2026Fast charging gets a full day's worth of battery in just 12 minutes.

Quick charge claimiMaker claim for usage from a short charge. Source notes identify the usage workload, such as normal use or sleep tracking.

Not available

Charge time12 minUse time24 h1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Charge your watch: charge Sense 2 for 12 minutes for 24 hours of battery life. The usage workload is not named.

Charge 0 to 80% (claimed)iMaker claim for charging an empty battery to 80%. Charger and approximate qualifiers belong in source notes.

45min5Maker product pagesupport.apple.com/en-us/102454Read 10 October 2026Apple Watch Series 7, Series 8 and Series 9 charge from 0 to 80 percent in about 45 minutes. Tested with the Magnetic Fast Charging USB-C cable and an Apple 20W USB-C Power Adapter.

Not available

Full charge time (claimed)iMaker advertised nominal full-charge duration. Approximate or theoretical maker estimates are allowed, with their conditions in source notes. Partial-charge intervals do not qualify. Measured 0 to 100% tests have a separate field.

Not available

120min1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Charge your watch: charging fully takes about 1-2 hours. The Google Store spec page states two hours and is stored.2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026Battery and power: the Oct 2022 Fitbit.com spec text states charge time (0-100%): two hours.

Measured

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Peak brightness (measured)iReviewer measurement. Source notes state screen area, mode and ambient light. A small-area peak claim cannot be replaced with a full-screen measurement.

Not available

Not available

Battery life (measured)iReviewer-observed mixed-use endurance. Source notes state case size, AOD, workout use and whether it was a complete discharge. Extrapolation from partial discharge is excluded.

Not available

144h18Measurementnotebookcheck.net/Fitbit-Sense-2-Smartwatch-review-Automatic-activity-recording.717608.0.htmlRead 23 October 2026Battery life: with all measurements active, worn around the clock, automatic training detection on, no extensive workouts and the always-on display off, the Sense 2 lasts exactly six days (144 h). Firmware and brightness are not stated. The always-on display test (just under four days) has no exact figure and is not stored.

Battery tests (measured)iReviewer-observed endurance, with case size and test settings in source notes. Partial-discharge projections are not stored as measured endurance.

AApple Watch Series 8

Not available

BFitbit Sense 2

Test	Hours (h)
Mixed use, always-on display off	144

Source18Measurementnotebookcheck.net/Fitbit-Sense-2-Smartwatch-review-Automatic-activity-recording.717608.0.htmlRead 23 October 2026Same test: always-on display off, all measurements active, automatic training detection, no extensive workouts. 6 days converted to 144 h. With the always-on display on it lasted just under four days, which is not stored as a number.

Full charge time (measured)iReviewer measurement from empty to full, not 0-80% or a charge from 5%. Source notes name the charger and case size.

Not available

95min18Measurementnotebookcheck.net/Fitbit-Sense-2-Smartwatch-review-Automatic-activity-recording.717608.0.htmlRead 23 October 2026Battery life: 0 to 99 percent after 85 minutes on a 24-watt power supply and another 10 minutes for the last percent. Stored as 95 minutes for 0 to 100 percent. 0 to 80 percent took one hour. Test unit with the supplied charging cable and a 24 W adapter. The maker claims two hours.

Strap

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Lug widthiDistance between standard strap attachment lugs, not the decorative width of a proprietary strap. Unknown for custom connectors unless the maker publishes lug width.

Not available

24mm3Maker product pagestore.google.com/us/product/fitbit_sense_2Read 23 October 2026The store shows an accessory shop headed Shop 24mm attach accessories. Fitbit publishes no lug width in a spec table, and the connector is proprietary, so this is the maker's attach size only.18Measurementnotebookcheck.net/Fitbit-Sense-2-Smartwatch-review-Automatic-activity-recording.717608.0.htmlRead 23 October 2026Case and features: the strap is 24 millimeters wide and can be changed without tools. It is not a standard clasp, so 24 mm is the strap width, not a lug width for standard straps.

Quick-release strapiThe supplied strap can be detached through its quick-release mechanism. Compatibility with quick-release replacement straps alone does not qualify.

Yes11Owner's manualsupport.apple.com/guide/watch/remove-change-and-fasten-watch-bands-apd3cc13d48f/26/watchos/26Read 10 October 2026Guide: hold the band release button, then slide the band across to remove it. Generic Apple Watch guide for watchOS 26, which Series 8 runs. No standard lug width is stated. Apple bands use a proprietary slide-in system.

Yes1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Change the band: slide the flat latch button toward the band, pull the band away. Attach by pressing until it clicks. No tools.

Strap systemiPublished attachment system and compatible case sizes. Proprietary connectors are distinguished from standard spring bars.

Not available

Proprietary latch connector. Fitbit Sense, Versa 3 and Versa 4 bands are compatible.1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Change the band: Fitbit Sense, Fitbit Versa 3, and Fitbit Versa 4 bands are compatible with Sense 2. Band latches on the back. No lug width is stated in the manual.

Strap materialiMaterial of the supplied strap for the stated package. Do not substitute material from another band sold separately.

Not available

Other1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Materials: the supplied band is a flexible, durable elastomer similar to the material used in many sports watches. Other preserves that wording without guessing silicone, HNBR or fluoroelastomer.

Strap

Not available

Classic band2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026What's in the box: Classic band (Small and Large).

Strap sizesiPublished wrist-circumference range for the stated strap or case. Source notes distinguish an overall compatible wrist range from one supplied strap size.

AApple Watch Series 8

Not available

BFitbit Sense 2

Size	Wrist (min) (mm)	Wrist (max) (mm)
Small	140	180
Large	180	220

Source1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Band size, printed page 63: Small band fits a wrist of 140 to 180 mm (5.5 to 7.1 in), Large band 180 to 220 mm (7.1 to 8.7 in). The Google Store page prints different ranges (130 to 180 mm and 165 to 220 mm). The manual is preferred. These are the supplied straps.

Regulatory

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FCC ID

Not available

XRAFB5211Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026USA FCC statement: Model FB521, FCC ID XRAFB521.

SAR limb (US)iPublished limb/wrist SAR for the stated base regional model under the US regime. Other case sizes or radio versions can differ. Head or body SAR is excluded.

Not available

Not available

SAR limb (EU)iPublished limb/wrist SAR for the stated base regional model under the EU regime. Other case sizes or radio versions can differ. Head or body SAR is excluded.

Not available

Not available

Other certifications

Not available

RED (2014/53/EU), UK Radio Equipment Regulations 2017, IEC 62368-1:2014, IEC 62368-1:2020 + A11:2020, ISED Canada (IC: 8542A-FB521)1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026EU section: Fitbit LLC declares Model FB521 compliant with Directive 2014/53/EU. UK section: Radio Equipment Regulations 2017. Safety Statement lists IEC 62368-1:2014 and IEC 62368-1:2020 + A11:2020. Canada section lists IC 8542A-FB521. These are model declarations, not medical, military or diving certifications.

In the box

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In the box

Apple Watch Series 8, Band/Loop, Apple Watch Magnetic Fast Charger to USB-C Cable (1m)1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Maker box: Apple Watch Series 8, Band/Loop, Apple Watch Magnetic Fast Charger to USB-C Cable (1m). Case material and band type depend on the selection.

Fitbit Sense 2, Classic band (small & large), Charging cable1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026What's in the box: watch with small band, charging cable and an additional large band.2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026What's in the box: Fitbit Sense 2 Classic band (Small and Large), charging cable.

Power adapter in boxiA mains/USB power adapter is supplied. A charging cable, inductive puck or charging dock alone does not count.

No1Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026No mains adapter in the box. The magnetic cable is not counted.

No1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026What's in the box lists the watch, bands and the charging cable. No power adapter. The cable plugs into a USB port or a UL-certified USB wall charger.

Links

Not compared

Product page

support.apple.com/en-us/1118481Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Exact Apple Watch Series 8 Tech Specs page, year introduced 2022. Data accurate as of product launch. No Series 9 or later value is copied.

store.google.com/us/product/fitbit_sense_23Maker product pagestore.google.com/us/product/fitbit_sense_2Read 23 October 2026Google Store product page for Fitbit Sense 2 (US).

Spec sheet

support.apple.com/en-us/1118481Maker product pagesupport.apple.com/en-us/111848Read 10 October 2026Same maker page. It is the complete Series 8 technical sheet.

store.google.com/us/product/fitbit_sense_2_specs2Maker product pagestore.google.com/us/product/fitbit_sense_2_specsRead 23 October 2026This page is the maker's technical specs page for Sense 2.

Manual

Not available

storage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0d1Owner's manualstorage.googleapis.com/support-kms-prod/Cxknk8y9NHEphUUIYGTQvRVIFq1RZyQuGQ0dRead 23 October 2026Fitbit user manual, version 3.1, hosted on the Google Health Help Center user manuals page.

EPREL registration numberiId in the EU energy label database. Each size or model of a series has its own id, so it is per variant.

Not available

Not available

Warranty

1 of 1 differ

Manufacturer warranty (source market)iThe maker's warranty period for the exact SKU or configuration and market named in the source note. It applies only to that stated market, not every regional variant. Statutory consumer rights are excluded. The base term is stored. An extension that needs registration goes in the source note.

Not available

1year8Maker product pagesupport.google.com/product-documentation/answer/14815834Read 23 October 2026Fitbit Limited Warranty: new products carry one year from purchase, two years for EEA residents who bought in the EEA. Devices bought on or after July 11, 2023 fall under the Google Hardware Warranty Center terms. Stored as the US one-year term.

Both are also in the API. Back to all smartwatches.