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Wearable comparison / Garmin / Forerunner 255
GARMIN

Forerunner 255

Watchreleased 2022MyBodyAI · Connects by upload

Garmin Forerunner 255 is a watch from 2022, sitting in the premium band at an indicative $349.

It reads 18 of the 33 signals this comparison tracks. Full coverage of activity. Nothing at all from body composition. Rarer readings it does take: Body Battery.

By sensor class: 10 at high accuracy and 3 at consumer grade. That grade is my classification of the hardware, not a lab test. Those readings come from an optical heart rate sensor, an optical blood oxygen sensor, a GPS receiver, a barometer and an accelerometer. Blood oxygen is measured during sleep, not continuously through the day.

Its 14 days per charge are the 39th longest of the 74 devices of its kind here that publish a figure. The transflective MIP screen can stay always on. Multi-band GPS. Rated 5ATM, fine for swimming. It weighs 49 g. On top of the tracking it also handles contactless payments. Case size 46mm. No subscription is required.

Display/battery variant catalogued for the buy comparison; health-signal capability mirrors Forerunner 265.

Key specs

Price
$349indicative US list price
Battery
14 d · GPS 30 h14 days smartwatch; GPS-only 30h; all-systems+multiband 16h (46mm)
Display
Transflective MIP · always-on
Water resistance
5ATM (swim)
GPS
Multi-band
Weight
49 g
Case size
46mm
Works with
iOS + Android
Subscription
Not required · Garmin Connectfree; no paywall
Extras
Contactless pay
Official store →

What it tracks

Heart & vitals

Resting heart rateHigh accuracy
HRVHigh accuracy
Blood oxygen (SpO2)High accuracy
Respiratory rateHigh accuracy

Sleep

Sleep durationHigh accuracy
Sleep stagesHigh accuracy
Sleep scoreHigh accuracy

Activity

StepsConsumer
Active minutesConsumer
CaloriesConsumer
WorkoutsHigh accuracy
Floorstracked
Distancetracked

Fitness

VO2maxtracked
Training loadtracked
Recovery / readinesstracked
Energy / Body BatteryHigh accuracy
All-day stressHigh accuracy
Screening, not a medical diagnosis. This device offers SpO2. These are wellness screening features, not a substitute for a clinical evaluation.
If you want to go deeper

Turn a supported wearable into daily health scores

MyBodyAI reads Fitbit, Oura, Polar and Withings by logging in, and Garmin from a data export, then builds daily recovery, sleep, load and immune scores, a biological age estimate, and early warnings. Optional, and separate from this comparison.

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