Lug width: how to find the right strap size
Lug width is the distance between the inside edges of a watch's lugs, where the strap attaches, measured in millimetres. It's the number you need to buy a strap: a watch with a 20 mm lug width needs a 20 mm strap. The most common lug widths for men's watches are 18, 20 and 22 mm, and smaller watches often use 12 to 16 mm.
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How to measure lug width
Remove the strap if you can, then measure the gap between the lugs with calipers or a ruler with millimetre markings. If you can't remove the strap, measure the strap's width right where it meets the case. The brand's website or the watch's manual usually lists it too.
Common lug widths
| Lug width | Typical watches |
|---|---|
| 12–16 mm | Smaller and women's watches, some vintage pieces |
| 18 mm | Many dress watches and vintage watches |
| 19 mm | Some vintage and smaller sports watches |
| 20 mm | The most common size for sports and everyday watches |
| 21 mm | Some sports watches from certain brands |
| 22 mm | Larger sports, dive and pilot watches |
| 24 mm and up | Large watches and some military styles |
A useful rule of thumb: lug width is often around half the case diameter.
Strap taper
Many straps get narrower towards the buckle, for example from 20 mm at the lugs to 16 mm at the buckle. Taper makes a strap look more elegant and feel lighter; a straight (non-tapered) strap looks sportier and more robust. When buying, check both numbers.
Strap length
Strap length is usually given as two numbers, for the long and short pieces (for example 120/75 mm), suited to an average wrist of around 16.5–18 cm. Smaller and larger wrists may need short or long versions. The aim is for the strap to sit comfortably in the middle holes.
Quick-release spring bars
Many modern straps have quick-release spring bars with a small lever, so you can change straps in seconds without tools. They make it much easier to rotate straps, and to experiment.
Track your straps, not just your watches
Straps change how a watch looks and feels, and most collectors have a drawer of straps they rarely use. WristLog.app keeps a catalogue of your straps with their own wear history, so when you log what you're wearing you can log the strap too, and see which ones, and which pairings, you actually reach for. The Strap Graveyard shows the ones you've stopped reaching for.
Common questions
Can I fit a 22 mm strap on a 20 mm watch?
No, a strap that's too wide won't fit between the lugs. A strap that's 1 mm narrower can sometimes fit but tends to look loose and can move along the spring bar. It's best to match the lug width exactly.
What's the most common lug width?
20 mm is the most common lug width for men's sports and everyday watches, followed by 22 mm and 18 mm.
How do I know my strap length?
Measure your wrist, then compare with the strap's listed length. Standard straps fit most wrists of around 16.5–18 cm; outside that range, look for short or long versions.
WristLog.app
See it for your own collection.
WristLog.app catalogues your watches from a photo and shows you how you really wear them. Free on iPhone and Android.
