What size watch strap do I need?
Watch straps are sized by lug width — the gap between the two lugs (the metal horns) where the strap attaches to the watch case. It is measured in millimetres, and it is the only measurement that has to be exact. Get the lug width right and the strap fits. Get it wrong by even 1mm and the strap will either not go in or will rattle.
How to measure lug width
- Remove the existing strap (or just measure around it if you would rather not).
- Measure the gap between the inside faces of the two lugs, not the outside of the case.
- Use a millimetre ruler or digital calipers. A steel ruler works fine — line the zero mark up with the inside edge of one lug and read where the inside edge of the other lug falls.
- Round to the nearest whole millimetre. Lug widths are almost always whole even numbers, and occasionally odd numbers on dress watches.
If you do not have a ruler to hand, the width is often printed on the back of the original strap near the buckle, or stamped inside the case lugs.
Common lug widths by watch size
As a rough guide, lug width is usually around half the case diameter:
- 28-32mm case — typically 14mm or 16mm
- 34-36mm case — typically 18mm
- 38-40mm case — typically 20mm
- 41-44mm case — typically 22mm
- 45mm and above — typically 24mm or 26mm
This is a guide, not a rule. Always measure if you can.
What if I measure an odd number?
Odd lug widths (19mm, 21mm, 23mm) are common on vintage watches and some dress watches. They are real, and you should buy that exact size rather than rounding. Our Croc Print straps cover every width from 12mm to 24mm, including all the odd sizes, and the Classic Cowhide and Soft Grain straps include 19mm and 21mm.
Does strap length matter too?
Less than you might think. Most straps are made to fit wrists from roughly 15cm to 20cm, with several buckle holes to adjust. If your wrist is under 15cm or over 20cm, look for straps described as short or long — otherwise standard length is fine.
Tapered straps
Some straps taper, meaning they are wider at the lug end than at the buckle. A 20mm strap tapering to 18mm still needs a 20mm lug width — the size quoted is always the lug end. Our Tapered Calfskin strap is one example.
Ready to find your strap?
Once you know your size, browse all our leather watch straps and filter by the width you need.