What size watch band do I need?
The size of a watch band is the lug width of the watch: the gap between the two lugs of the case, in whole millimetres. Look it up, read it on the watch strap you already have, or measure it. Then choose the length by your wrist.
The most common size: 36.4% of 41,485 measured watches take it. Measured 2026-10-24.
The watch decides the size, not you
A watch band has to fill the gap between the lugs of the case exactly. That gap is the lug width of the watch, and it is a property of the case: a 20 mm case gap takes a 20 mm watch band, nothing else. Across 41,485 measured watches, 20 mm is the most common size (36.4%), then 22 mm (16.8%). Odd numbers are real too: 18.2% of watches take 19, 21, 23, 17 or 15 mm.
2,640 watches (5.7%) take no standard watch band at all, because the bracelet is built into the case. If yours is one of them, read the guide to watches with an integrated bracelet: it explains what fits instead.
Three ways to find your size, in this order
- Look up your reference. The reference number is engraved on the case back or between the lugs. Search it on this site: the lug width of the watch is on its page, measured for that reference, not guessed from the name of the watch family.
- Read the watch band you already have. Most watch bands carry their width stamped on the back, near the spring bar hole: a small «20» means 20 mm at the lugs. Read the end that goes into the case, not the end with the buckle, because many watch bands get narrower towards the buckle.
- Measure the gap. Take the watch band off and measure the inside gap between the two lugs with a caliper or a ruler, in whole millimetres. The measuring guide shows the two mistakes to avoid.
The one mistake that makes people buy one size too small
The case diameter is not the size of the watch band. A 40 mm case does not take a 40 mm watch band, and there is no fixed rule between the two numbers: at the same case diameter, references take many different lug widths. Case size and lug width shows how far apart they are.
Then the length, by your wrist
Width is set by the watch. Length is set by you: measure your wrist and read the watch strap length guide. The full table of widths, with the watches that take each one, is in the watch strap size chart.
Check your own reference
Family averages are the reason people order the wrong size. Your reference has its own measured number, and it is in the database.
Search your referenceOther questions
- Why will no strap fit my watch?5.7% of watches have no lug width at all. Here is what to do instead.2,640
- What length watch strap do I need?Ready-made straps come in one length only. Whether that length reaches you is a different question.75/115 mm
- Which spring bar does my watch need?Length is the lug width of the watch; diameter is decided by the brand. Rolex, Omega and Tudor have their own, the rest take a standard 1.8 mm spring bar.
- How do I change a watch strap?A spring bar tool and five minutes. The two facts to know first, the five steps, and the pull-test that is the only check you have.