Watch Strap Width Explained: How to Never Buy the Wrong Size Again
Watch strap width, measured in millimeters between the inside of the lugs, is almost always printed on the original strap's underside or in the watch's spec sheet; common widths range from 16mm to 22mm, and as a rough proportional guide, strap width often sits close to half the case diameter.
Frequently Asked Questions
Can I put any width strap on any watch?
No — the strap width must exactly match the lug opening; there is no meaningful tolerance for a mismatched width.
Do quick-release straps change the measurement process?
No — quick-release spring bars still require the exact lug width; they only simplify the tool-free swap process, not the sizing itself.
How to measure it if it isn't marked
Measuring directly between the inner edges of the lugs where the strap attaches gives the precise number, usually in even millimeter increments (18mm, 20mm, 22mm, etc.).
Some watches use a tapered strap that's wider at the lugs and narrower at the buckle; both measurements matter if you're replacing the strap with a non-original one, since not all straps taper the same amount.
Rough proportional guidance
A common approximate rule pairs a roughly 20mm strap with a 38-40mm case, adjusting up or down a couple of millimeters as case size increases or decreases.
Undersized straps relative to the lug width leave visible gaps at the connection point, while oversized straps won't physically fit the spring bar attachment at all.