How do I measure my own lug width?

Three steps

1. Take the current band off. Measuring around it costs you the two thicknesses of leather or steel sitting in the gap, and that is exactly the error that sends people one size down.
2. Put a caliper inside the gap. A ruler works if the lugs are open enough to read it. Measure at the narrowest point: many lugs curve inward, and the widest part of the opening is not the part that holds the band.
3. Read it in whole millimetres. Watch cases are drawn in whole numbers. If you read 20.4, the answer is 20. If you read something clearly between two numbers, measure again.

The two readings that are wrong

A half size. 20.5 mm does not exist as a lug width. It means the caliper was not flat against the inside of the lugs, or it was reading the curve.

The case diameter. A 40 mm case does not take a 40 mm band, and there is no fixed ratio between the two. Cases of the same diameter routinely take different band sizes.

An odd number, on the other hand, is usually correct. 19 and 21 mm are real sizes and roughly one watch in six takes one of them.

Or skip the caliper

The measurement has already been taken for 42,813 watches. If yours is among them, the number is on its page, along with the bands made in that size.

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.

Other questions

• Does lug width change within the same watch family?67.7% of watch families use more than one lug width. Knowing the family is not enough.67.7%
• What is the most common lug width?20 mm, on 38.8% of measured watches. What the rest of the distribution looks like.20 mm
• Can a watch have an odd lug width like 21 mm?One watch in six takes an odd size. 21 mm is not a rounding error.16.3%
• Why will no strap fit my watch?6.1% of watches have no lug width at all. Here is what to do instead.2,632

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