Watch strap fitting guide
How to Find Your Watch's Lug Width
Measure the gap between the inside edges of the lugs, in millimetres. That number is the strap width to order.
Already have a strap? Check the first number printed underneath: 22-18 means a 22 mm lug width and an 18 mm buckle end.
Fastest first
Three ways to get your number
If two of them agree, you have your width.
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1 · Quick check
Your current strap
Look underneath for a pair like 22-18: the first number is the lug width. No print? Measure straight across the very end that sits between the lugs, as above: 22.0 mm.
Further down the strap tapers and reads too small. If the strap isn't original to the watch, confirm with method 2 or 3.
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2 · No tools
The watch specifications
Search "[brand] [exact reference] lug width" and check the maker's specification page or manual. It may be listed as band width, strap width or interhorn width.
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3 · Most accurate
Measure between the lugs
With the strap off, open the small inside jaws of the calipers between the lugs until each touches an inside edge, as above: 22.0 mm.
Calipers: keep the decimal, such as 22.0 or 20.5. Ruler: line up zero with one inside edge, read at the other to the nearest mm, and measure twice. Half sizes are fine: we make them.
What your number means
Lug width vs buckle width
Only the lug width has to match your watch. Most leather straps taper toward the buckle; on our straps the buckle end is equal to or narrower than the lug end. Standard straps come as 16-12, 17-14, 18-14, 19-16, 20-16, 21-18, 22-18, 23-20 and 24-20, and selected styles also offer 20-18. Any other pair, half sizes included, is made in the custom builder.
Lug width vs case size
Case diameter, lug-to-lug and lug width are three separate specifications. Two 42 mm watches can need different straps, so never work it out from the case size.
Lug width vs strap length
Width says nothing about length. Length comes from your wrist and the watch's lug-to-lug: see the size guide.
Odd and half sizes
19 mm? 20.5 mm? We cut the exact width.
A strap even 1 mm off leaves gaps or bunches at the lugs, so don't size up or down. Every Cernir strap is made to order: all ready styles come in 16 to 24 mm including 17, 19, 21 and 23 mm, and the custom builder makes any other width to your measurement, half millimetres included.
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Half-millimetre widths
20.5 or 22.5 mm? Measure twice with calipers, then enter the exact width in the custom builder. We make it as measured.
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Curved or hooded lugs
Measure where the spring bar sits. Our Curved End is a curved finish only, not shaped to your case, so a small gap can remain.
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Integrated fittings
If the strap fits into the case itself, a standard spring-bar strap may not work. Send us your reference and photos first.
Still unsure? We'll check before we cut.
Send us the brand, the exact reference number, a photo of the watch face and a photo of the gap between the lugs.
Lug width questions
What is the most common lug width?
20 mm, followed by 18 mm and 22 mm. Common doesn't mean yours, so check before ordering.
Can I fit a 22 mm strap on 21 mm lugs?
We don't recommend it: it bunches between the lugs, and a narrower strap leaves gaps and loads the spring bars unevenly. Order 21 mm instead.
Can you make half sizes like 20.5 mm?
Yes. Enter your exact measurement in the custom builder and we make the strap to that width.
Can I measure without removing the strap?
Yes. Measure across the strap right where it meets the case, or check the specifications. For the most accurate reading, measure between the lugs with the strap off.
Do your straps come with spring bars?
Yes. Standard straps come with two quick-release spring bars fitted for standard lug fittings. On a custom strap, you choose quick-release or regular bars. Spring bars must suit both the watch and the strap width; integrated or brand-specific fittings are not covered. See how to change a watch strap.
Does lug width tell me the strap length?
No. Length depends on your wrist and your watch's lug-to-lug. Our size guide uses both to suggest S, M or L.