How-To · 3 min read
How to Measure Lug Width
The single most important number on your wrist. Get it right in under a minute with a ruler.
Lug width is the distance between the two lugs of your watch case - the gap where the strap slots in. It is always measured in millimetres and it is the single most important number when shopping for a new strap. Get it wrong and the strap will either rattle around or refuse to fit at all.
What you need
- A millimetre ruler, calipers, or a printable lug-width gauge
- Your watch, strap removed if possible
- Two minutes and decent light
The measurement, step by step
- Turn the watch face down on a flat surface.
- Place the ruler flush against the inside of one lug.
- Measure the gap to the inside of the opposite lug, ignoring the case curve.
- Round to the nearest even number - most watches are 18, 20, 22 or 24mm.
What if you don't have a ruler?
Search for a printable lug gauge, scale it to actual size, hold the case over the slot it fits cleanly into, and you have your answer. Failing that, take a photo of the back of the watch next to a coin - the case-back diameter is usually stamped on the rear and you can work backwards.
If you are between sizes, always size down. A 19mm gap takes an 18mm strap, never a 20.
