Watch & Band Size Guide
Find your watch case size, band size, and lug width by wrist measurement. Apple Watch, Garmin, Fitbit, traditional watches.
Apple Watch sizing
Apple Watch comes in 2 case sizes per series. The case size determines which bands fit.
| Series | Small case | Large case | Wrist fit |
|---|---|---|---|
| SE / 9 / 10 | 40 / 41 mm | 44 / 45 / 46 mm | Small: under 17cm. Large: over 17cm |
| Ultra / Ultra 2 | — | 49 mm only | Best on wrists 16cm+ |
Band compatibility: Small-case Apple Watches use 38/40/41mm bands. Large-case use 42/44/45/46/49mm bands. Bands are NOT interchangeable between sizes.
Traditional watch lug width
Lug width is the distance between the two "lugs" (where the band attaches). Measure existing band in mm.
| Watch type | Common lug width |
|---|---|
| Women's dress (28-32mm case) | 12-16mm |
| Mid-size unisex (34-38mm) | 18mm |
| Men's dress (38-40mm) | 20mm |
| Men's sport (42-44mm) | 22mm |
| Large diver/pilot (44-46mm) | 22-24mm |
| Rolex Submariner / GMT | 20mm |
| Omega Speedmaster | 20mm |
FAQ
How should a watch fit?
Snug enough that the case stays centered on top of your wrist. Loose enough to fit 1 fingertip under the band. Should not slide more than 2cm when you move your arm.
Apple Watch 40mm vs 44mm — which should I buy?
Wrists under 6.7" (17cm): 40/41mm. Wrists over 6.7": either works — try in store. 44/45mm has a noticeably larger display and longer battery.
Can I shorten a metal watch band?
Yes — most have removable links. Bring to a jeweler or watch shop for $10–25. Some Apple Watch metal bands also have removable links. Save the removed links in case you sell the watch.
Why doesn't my watch band fit my watch?
Lug width mismatch. Measure the gap between lugs in mm and buy a band of the same width. Standard lug widths come in 2mm increments (18, 20, 22, 24mm).
Garmin / Fitbit band sizes?
Garmin uses "Small/Medium" (130-185mm wrist) and "Large" (160-220mm wrist) on most models. Fitbit Sense/Versa: S (140-180mm) and L (180-220mm). Always check the specific model's range.