How to measure lug width and pick the right strap size
Lug width decides which straps fit your watch. How to measure it, what the buckle width and lug-to-lug mean, and which strap length suits your wrist.
What lug width is
The lugs are the four horns that hold the strap. Lug width is the gap between them, measured inside, in millimetres. A strap has to match it exactly: a strap 1 mm narrow leaves gaps and a strap 1 mm wide will not go in. Most watches have an even number, usually 18, 20 or 22 mm, but 19 and 21 mm exist.
Measure it
- Look it up first. The maker often lists it in the specs, or the strap that came with the watch has it stamped on the back.
- Otherwise, use a caliper or a ruler with millimetre marks and measure the gap between the inner faces of two lugs, at the spring bar.
- Measure twice, at the top and bottom lugs, and round to the nearest whole millimetre.
Buckle width and lug to lug
- Most leather and rubber straps taper by about 2 mm, so a 20 mm strap has an 18 mm buckle. The taper changes how the watch looks: more taper reads dressier.
- NATO straps do not taper, and bracelets usually narrow by about 4 mm towards the clasp.
- Lug to lug is the length of the watch from lug tip to lug tip. If it is longer than your wrist is wide, the lugs overhang and the watch looks too big, whatever its diameter.
Strap length
Two-piece straps are sold by the length of each piece. Regular (120/75 mm) fits most wrists from about 16 to 19 cm. Pick short (110/70 mm) below that and long (130/80 mm) above it. The strap matcher works it out from your wrist size and the watch.