Watch Size Calculator
Enter your wrist size to see which case diameters and lug-to-lug lengths should suit you, then check any watch against it before you buy. The drawing is to scale, so you can see where the lugs land on your wrist.
Wrap a strip of paper around your wrist where you wear a watch, just above the wrist bone, mark it and measure it flat.
For the most accurate lug-to-lug limit, measure straight across the top of your wrist, from edge to edge of the flat part, with a ruler. Leave it blank and we estimate it.
Case width is the diameter, not counting the crown. For square watches, use the width across the case.
Top view to scale. The band is the flat top of your wrist, and the lugs turn red where they overhang it.
How This Watch Size Calculator Works
Two numbers decide whether a watch fits: the case width, which sets how big the watch looks, and the lug-to-lug length, which decides whether it physically sits on your wrist. The calculator gives you a starting range for each, based on your wrist size.
- Case width. The suggested range comes from the widely used guideline in the table below. It is a matter of taste, so treat it as a starting point rather than a rule.
- Lug to lug. A watch fits when its lug-to-lug length is no longer than the flat top of your wrist. If you do not enter that measurement, we estimate it as about 30% of your wrist circumference, which matches common fitting advice: a 47mm lug-to-lug watch, for example, is often said to start overhanging on wrists under about 6.25 inches.
- Thickness. Watches over about 13mm thick can catch on shirt cuffs, while dress watches are usually under 10mm.
Watch Size Chart by Wrist Size
| Wrist circumference | Typical case width | Estimated max lug to lug |
|---|---|---|
| Under 6 in (15.2 cm) | 32 to 38mm | up to about 45mm |
| 6 to 6.5 in (15.2 to 16.5 cm) | 34 to 40mm | about 46 to 49mm |
| 6.5 to 7 in (16.5 to 17.8 cm) | 38 to 42mm | about 50 to 53mm |
| 7 to 7.5 in (17.8 to 19 cm) | 40 to 44mm | about 53 to 57mm |
| 7.5 to 8 in (19 to 20.3 cm) | 42 to 46mm | about 57 to 61mm |
| Over 8 in (20.3 cm) | 44 to 48mm | 61mm and up |
Dress watches usually look best at the smaller end of each range, and dive and sports watches at the larger end.
How to Measure Your Wrist
- Cut a thin strip of paper or use a piece of string.
- Wrap it around your wrist where you wear a watch, usually just above the wrist bone, snug but not tight.
- Mark where it overlaps, lay it flat and measure it against a ruler.
- For the flat top width, lay a ruler across the top of your wrist and measure between the points where the wrist starts to curve away.
Why Lug to Lug Matters More Than Diameter
Two watches with the same diameter can wear very differently. A 42mm Seiko SKX007 has a lug-to-lug of about 46mm, while a 42mm Omega Seamaster Diver 300M measures about 50mm. On a smaller wrist, that 4mm decides whether the lugs sit on top of the wrist or hang past its edges. Case shape, lug curve and bezel width all change how big a watch looks, which is why the drawing above is more useful than the diameter alone.
For a longer explanation with examples, read our guide on how to pick the right watch size for your wrist, or compare specifications side by side with our watch comparison tool.
Frequently Asked Questions
What size watch should I wear for a 6.5 inch wrist?
A 6.5 inch (16.5 cm) wrist usually suits a case width of about 36 to 41mm and a lug-to-lug of up to about 49 or 50mm. Enter your own measurements above for a closer estimate.
What size watch fits a 7 inch wrist?
Most 7 inch (17.8 cm) wrists suit 38 to 43mm cases and a lug-to-lug of up to about 53mm, so most mainstream sports and dive watches fit.
Is a 40mm watch too big?
For most adult wrists, no. A 40mm watch sits in the middle of the usual range. What matters more is its lug-to-lug length compared with the flat top of your wrist.
What is lug to lug on a watch?
Lug to lug is the distance from the tip of the top lugs to the tip of the bottom lugs, measured across the watch. It is the best single number for judging whether a watch will overhang your wrist.