Strap fitting guide

How to Find Your Watch's Lug Width

Before you buy a strap, you need one number: your lug width. Here's how to find it in under a minute.

The basics

What is lug width?

Lug width is the distance between the two lugs of your watch case — the gap where the strap sits. It's marked as “A” in the diagram, measured in millimetres.

A strap must match this width exactly, or it won't fit.

Reading Delugs widths (e.g. 20-16): the first number (20) is the lug width — the one that must match your watch. The second number (16) is the buckle width.

Why it matters

Lug width determines fit. Too narrow and the strap rattles; too wide and it won't seat between the lugs at all. Get this one measurement right and any strap of that width will fit your watch.

Three ways to find your lug width

From quickest to most accurate.

Fastest

Look it up

Search your watch's brand and model plus “lug width” — the maker's site or a trusted forum often lists it. Or use our Strap Finder, which lists the exact lug width for every watch model we cover.

DIY

Measure it yourself

Rest a ruler or calipers across the lugs — you don't even need to take the strap off. Line up with the inner edge of each lug; lug widths are almost always whole numbers.

See how below

Most accurate

Use the Lug Measurement Tool

Our credit-card-sized tool has precision notches for 14 lug widths. Slot it between the lugs and read the number — no guesswork, no caliper required.

Learn more

How to measure it yourself

No special tools needed — a ruler works, and you don't even have to take your strap off.

Take the strap off — optional

You don't have to remove your strap or bracelet to measure. But taking it off gives you a clear, unobstructed view of the lugs and the most accurate reading.

Line up a ruler with the lugs

Rest a ruler or pair of calipers across the watch where the strap meets the case — with the strap on or off — and align the marks with the inner edge of each lug.

Read the width in millimetres

The gap between the lugs is your lug width — almost always a whole number. Match it to the first number of a Delugs strap (e.g. a 20mm lug width takes a 20-16 strap).

Reusing your own buckle or clasp?

How to measure your buckle width

Most people can skip this — every Delugs strap comes with its own buckle. But if you want to keep a buckle you already own, you'll need its width too.

This is the second number in a Delugs width: the “16” in 20-16.

How to measure it: measure the inner gap of your buckle — the space between the two posts where the spring bar sits — or simply measure the width of the strap end currently fitted to it. That number, in millimetres, is your buckle width.

Order a custom strap

Know your lug width? Find compatible straps.

Our Strap Finder lists the exact lug width for every watch model and shows you every Delugs strap that fits.

Shop all straps

Frequently asked questions

What if my watch falls between two widths?

It's rare, but some watches sit between sizes (e.g. 17.5mm). Round to the nearest whole number, or contact our team and we'll advise on the best fit. Vintage watches in particular sometimes use odd widths or shallow spring-bar plots.

What lug widths do you stock?

Our ready-stock straps come in 16, 17, 18, 19, 20, 21, 22, 24 and 26mm. Need something else? Those can be custom made.

What does a width like “20-16” mean?

The first number (20) is the lug width — the one that must match your watch. The second number (16) is the buckle width. You only need to match the first number to your watch's lug width.

Do I measure at the top or bottom of the case?

If your lugs are symmetrical (most watches), there's no difference. Either side gives the same number.