How to measure your wrist for a smartwatch
Short answer: Wrap a paper strip or soft tape around your wrist just behind the wrist bone, mark where it meets, and measure the length. Then compare it with the watch's case size and band range. A case that fits within your wrist's width sits flat and reads sensors accurately.
Last verified September 26, 2026.
Measure in three steps
- Wrap a strip of paper or a soft tape snugly around your wrist, just behind the wrist bone, where you would wear the watch.
- Mark where the end meets the strip and measure that length. This is your wrist circumference.
- Measure the flat width of the top of your wrist. A case wider than this overhangs and tilts.
Match the numbers
- Case size is the diameter in mm. Smaller cases (around 38 to 42 mm) suit small wrists. Larger cases (around 46 mm and up) suit larger wrists and bigger screens.
- If you are between sizes, choose by comfort and by whether you want the larger display, not by brand.
- Bands often come in several lengths. Check the maker's band sizing before you buy.
- Sensor accuracy depends on skin contact. A watch that slides or lifts gives worse heart-rate readings.
Case sizes in our catalog
| Case size | Models |
|---|---|
| Up to 42 mm | 46 |
| 43 to 45 mm | 64 |
| 46 mm and up | 137 |
Up to 42 mm (46)
Amazfit Active, Amazfit GTS 2, Amazfit GTS 2e, Apple Watch SE (2nd gen), Apple Watch SE 3, Apple Watch Series 10, Apple Watch Series 11, Apple Watch Series 12, Apple Watch Series 9, COROS Apex 4, COROS PACE 3, COROS Pace 4, Fitbit Sense 2, Fitbit Versa 3, Galaxy Watch 3, Galaxy Watch 5, Galaxy Watch 6, Galaxy Watch 7, Galaxy Watch 8, Galaxy Watch 9, Garmin Forerunner 170, Garmin Forerunner 570, Garmin Forerunner 70, Garmin Venu 4, Garmin Vivoactive 6, Huawei Watch 5, Huawei Watch 6, Huawei Watch GT 4, Huawei Watch GT 5, Huawei Watch GT 6, Huawei Watch GT 7, Maxcom FW27 Selen, Maxcom FW28 Selen Mini, Mibro Watch Lite, POCO Watch, Pixel Watch (1st gen), Pixel Watch 2, Pixel Watch 3, Pixel Watch 4, Pixel Watch 5, Realme Watch (1st gen), Samsung Galaxy Fit3, Withings ScanWatch 2, Withings ScanWatch Light, Withings ScanWatch Nova, Xiaomi Watch S4 41mm
43 to 45 mm (64)
Amazfit Active 2 (round), Amazfit Active 2 Square, Amazfit Active 3 Premium, Amazfit Bip 3 Pro, Amazfit Bip 5, Amazfit Bip 5 Unity, Amazfit GTS (1st gen), Amazfit GTS 4, Amazfit Verge Lite, Apple Watch SE (2nd gen), Apple Watch SE 3, Apple Watch Series 9, CMF Watch Pro 2, Denver SW-162, Denver SWGL-149, Galaxy Watch 3, Galaxy Watch 5, Galaxy Watch 5 Pro, Galaxy Watch 6, Galaxy Watch 6 Classic, Galaxy Watch 7, Galaxy Watch 8, Galaxy Watch 9, Garmin Approach S12, Garmin Fenix 9, Garmin Fenix 9 Pro, Garmin Instinct 3, Garmin Venu 4, Garmin Venu X1, Honor Watch 4, Huawei Watch 6 Pro, Huawei Watch Fit 3, Huawei Watch Fit 4, Huawei Watch Fit 4 Pro, Kospet ORB, Maxcom FW100 Titan Valkyria, Maxcom FW26 Oxygen Pro, Maxcom FW42, Maxcom FW73 Onyx, Maxcom FW74 Aurum Slim, Mibro C4, Mibro GS Active, Mibro Watch A1, Mibro Watch A3, Mibro Watch C3, Mibro Watch Fit, Mibro Watch Lite 2, Mibro Watch Lite 3, Mibro Watch Lite 3 Pro, Mibro Watch T1, Mibro Watch T2, Mibro Watch X1, OnePlus Watch Lite, Pixel Watch 3, Pixel Watch 4, Pixel Watch 5, Polar Ignite 2, Polar Ignite 3, Polar Pacer, Polar Pacer Pro, Realme Watch R100, SPC Smartee Duo Velvet, Tracer SM7 Astral/Shadow, Tracer SMW9A Spark
46 mm and up (137)
ASUS VivoWatch 5, ASUS VivoWatch 6, Amazfit Active Edge, Amazfit Balance, Amazfit Balance 2, Amazfit Balance 3, Amazfit Bip 6, Amazfit Cheetah 2 Pro, Amazfit Cheetah 2 Ultra, Amazfit GTR 2, Amazfit T-Rex 3, Amazfit T-Rex 3 Pro, Amazfit T-Rex Ultra 2, Apple Watch Series 10, Apple Watch Series 11, Apple Watch Series 12, Apple Watch Ultra 2, Apple Watch Ultra 3, Apple Watch Ultra 4, Blackview W10 Pro, Blackview W50 Pro, Blackview W60, Blackview W70 Pro, Blackview W80 Pro, CMF Watch 3 Pro, COROS Apex 4, COROS NOMAD, COROS PACE Pro, COROS Vertix 2S, Denver SW-500, Denver SWC-185, Denver SWC-187, Denver SWC-195, Denver SWC-342, Denver SWC-387, Galaxy Watch 6 Classic, Galaxy Watch 8 Classic, Galaxy Watch Ultra (2024), Galaxy Watch Ultra (2025), Garett Compass GPS, Garmin D2 Mach 2 Pro, Garmin Enduro 2, Garmin Enduro 3, Garmin Fenix 8 Pro AMOLED, Garmin Fenix 8 Pro MicroLED, Garmin Fenix 9, Garmin Fenix 9 Pro, Garmin Forerunner 570, Garmin Forerunner 970, Garmin Instinct 3, Garmin Tactix 7 AMOLED, Garmin quatix 8 Pro, Garmin tactix 8 AMOLED, Garmin tactix 8 Cerakote Edition, Garmin tactix 8 Solar, Honor Choice Watch 2 Epic, Honor Choice Watch 2 Pro, Honor Watch 6, Huawei Watch 5, Huawei Watch 6, Huawei Watch 6 Pro, Huawei Watch D2, Huawei Watch D3, Huawei Watch GT 4, Huawei Watch GT 5, Huawei Watch GT 6, Huawei Watch GT 7, Huawei Watch GT 7 Pro, Huawei Watch GT Runner 2, Huawei Watch Ultimate, Huawei Watch Ultimate 2, Imilab W01, Kospet Magic P10, Kospet Magic R10, Kospet Pulse, Kospet Tank M3, Kospet Tank M3 Ultra, Kospet Tank M4, Kospet Tank M4C, Kospet Tank S2, Kospet Tank T2 Special Edition, Kospet Tank T3 Ultra, Kospet Tank T3 Ultra 2, Kospet Tank T4, Kospet Tank T4C, Kospet Tank X2 Ultra, Lenovo Watch S2 Pro, Maimo Saphir Watch (WT1004), Maimo Watch R (70mai), Maxcom FW110 Titan Chronos, Maxcom FW58 Vanad Pro, Maxcom FW65 Iron, Maxcom FW66 Iron R, Maxcom FW67 Titan Pro, Maxcom FW76 Gal, Mibro GS Active 2, Mibro GS Explorer, Mibro GS Explorer S, Mibro GS Pro, Mibro GS Pro 2, Mibro Watch GS, Mibro Watch GT, Moto Watch 47, OnePlus Watch 2, OnePlus Watch 2R, OnePlus Watch 3, OnePlus Watch 4, Polar Grit X Pro, Polar Grit X2 Pro, Polar Vantage V3, Realme Watch S2, Redmi Watch 4, Redmi Watch 5, SPC Smartee 4G Senior, SPC Smartee Duo 3, SPC Smartee Duo Vivo 2, Suunto Core 2, Suunto Race 2, Suunto Run 2, Suunto Vertical, Suunto Vertical 2, TicWatch Atlas, Tracer GP-Fit2, Tracer GP-Run, Tracer SMK12 Stellar, Tracer SMK15 Aurora, Tracer SMR11 Hero, Tracer SMW9 X-TRO, Ulefone Armor Watch Pro, Ulefone Armor Watch Ultra, Xiaomi Watch 2, Xiaomi Watch 2 Pro, Xiaomi Watch 5, Xiaomi Watch S1, Xiaomi Watch S1 Active, Xiaomi Watch S4, Xiaomi Watch S5
A model with more than one size appears in each matching group. 35 models list a shape or a single size without a number (square, round, one size), and 57 have no size listed or list it in another form. They are not grouped here.
Try the fit tool
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Sizes and bands change between versions. Check the maker's sizing before buying. Some buy links may earn WristGuide a commission at no extra cost to you. See our methodology and affiliate disclosure.