How to size a watch to your wrist
Measure your wrist circumference with a tape measure and use it as a starting point: under 16cm suits a 34 to 38mm case, 16 to 18cm suits 38 to 42mm, and above 18cm suits 42 to 46mm. But diameter is the least important of the three measurements that determine fit. Lug-to-lug length decides whether a watch sits properly at all.
| Wrist circumference | Case diameter | Max lug-to-lug |
|---|---|---|
| Under 15cm | 32 to 36mm | Around 44mm |
| 15 to 16cm | 34 to 38mm | Around 47mm |
| 16 to 17cm | 38 to 41mm | Around 50mm |
| 17 to 18cm | 40 to 43mm | Around 52mm |
| Over 18cm | 42 to 46mm | Around 55mm |
Measure the wrist first
Wrap a soft tape measure around your wrist just below the wrist bone, where the watch will actually sit. Keep it snug but not tight. If you do not have a tape measure, wrap a strip of paper, mark it and measure the strip against a ruler.
Do this before looking at any watches. Working from a measurement stops you anchoring on whatever size you happen to own already.
Lug-to-lug is the measurement that matters
Lug-to-lug is the distance from the tip of the top lugs to the tip of the bottom lugs — the full length of the case. It determines whether the watch sits flat on your wrist or overhangs the edges.
A 40mm case with long straight lugs can wear larger than a 44mm case with short curved ones. If the lug-to-lug exceeds the flat width of your wrist, the lugs will lift the case and the strap will angle awkwardly. This is the single most common sizing mistake and diameter alone will not warn you about it.
Thickness decides whether it fits under a cuff
A dress watch is typically 7 to 10mm thick and slides under a shirt cuff without catching. Dive watches commonly run 13 to 16mm, and above about 12mm you will notice it snagging.
Thickness also affects how large a watch looks. A thick 40mm watch reads as bigger than a slim 42mm one, because the case sits proudly rather than hugging the wrist.
Where the rules stop applying
These are starting points, not prescriptions. Deliberate oversizing is a legitimate style — plenty of people wear a 44mm watch on a 16cm wrist and it looks intentional rather than wrong. Vintage-styled pieces run deliberately small for the same reason.
Use the measurement to narrow a field of several thousand watches down to a few hundred. Then buy the one you like.
Common misconceptions
Case diameter tells you how a watch will fit.
It tells you least of the three. Lug-to-lug determines whether it sits flat, and thickness determines how large it reads.
Men should wear large watches and women small ones.
Fit follows wrist size, not gender. Plenty of 36mm watches are marketed to men and plenty of 40mm ones to women.
A slightly loose bracelet is fine.
A watch that slides down onto the wrist bone will wear uncomfortably and read as the wrong size regardless of its dimensions.
Case sizes across the watches we list
Case size is recorded in millimetres on nearly every watch on the site, grouped below into the bands used across the browse filters.
| Case size | Watches | From |
|---|---|---|
| Under 30mm | 790 | £19.99 |
| 30-33mm | 501 | £22.49 |
| 34-36mm | 558 | £14.99 |
| 37-39mm | 832 | £19.99 |
| 40-42mm | 1,570 | £22.99 |
| 43-45mm | 1,009 | £27.99 |
| 46-49mm | 215 | £29.99 |
| 50mm and over | 142 | £29.99 |
Based on 5,676 watches listed and in stock. Updated continuously.