How to Measure Your Watch Band Size: Lug Width, Spring Bars & Wrist Fit | Simple Guide

How to Measure Your Watch Band Size: A Simple Guide for Every Watch

If you've ever wondered, "Which watch band size do I need?", you're not alone. Watch bands are sized by three separate measurements, and getting any one of them wrong means a band that won't fit. The good news is that each one takes less than a minute to check with a ruler or a tape measure.

In this guide, we'll walk you through measuring your lug width, checking your spring bars, and measuring your wrist — then choosing between our 22 mm and 24 mm universal bands.

Step 1: Measure Your Lug Width

The lug width is the single most important number. The lugs are the two small horns on each side of the watch case that hold the band in place. The lug width is the distance between them, measured in millimetres.

  • Take off your current band so you can see the gap clearly.
  • Lay a ruler across the gap between the inside edges of the two lugs.
  • Read the measurement in millimetres. Common widths are 18, 20, 22 and 24 mm.
  • If you can't remove the band, measure the band itself where it meets the case — it is the same width as the lug gap.

Many bands are also stamped with their width on the underside near the spring bar, as ours are. A band must match the lug width exactly: a 22 mm band will not fit 24 mm lugs, and a 24 mm band will not fit 22 mm lugs.

Step 2: Check Your Spring Bars

Spring bars are the small spring-loaded pins that hold the band between the lugs. There are two things to check:

  • Diameter. Our universal bands come fitted with 1.8 mm spring bars, the standard for most sport and dive-style watches. Older or thinner watches sometimes use 1.5 mm pins; the lug holes on those watches will still accept a 1.8 mm bar in most cases, but check the fit before wearing.
  • Quick-release or standard. A quick-release spring bar has a tiny lever on the back of the band. Slide it toward the centre of the band to retract the pin and lift the band away — no spring-bar tool needed. Standard spring bars need a tool to compress them.

All of our universal bands use quick-release spring bars, so fitting and swapping them takes seconds.

Step 3: Measure Your Wrist

Wrist size decides whether the band's buckle holes will give you a comfortable fit. Measure around the wrist, not flat:

  • Wrap a soft tape measure snugly around your wrist exactly where you wear your watch — usually just above the wrist bone.
  • No tape measure? Wrap a strip of paper or string around your wrist, mark where it overlaps, and lay it flat against a ruler.
  • Read the measurement in millimetres (or inches). Don't pull tight — the band should sit comfortably with room for the watch to move a little.

Our bands fit these wrist sizes when worn on a watch or a Catalyst case:

  • 22 mm band: 133–210 mm (5.2–8.2 in)
  • 24 mm band: 140–215 mm (5.5–8.4 in)

Step 4: Choose Between the 22 mm and 24 mm Band

Pick the band whose width matches your lug measurement from Step 1. If you are fitting the band to a Catalyst waterproof case for Apple Watch, the case size decides the width:

  • 22 mm (Small) fits Catalyst cases for Apple Watch 38 mm, 40 mm and 41 mm.
  • 24 mm (Large) fits Catalyst cases for Apple Watch 42 mm, 44 mm and 45 mm.

Both sizes share the same strap-piece lengths — a 115 mm long piece and a 75 mm short piece — a stainless steel pin buckle with a keeper loop, and soft hypoallergenic silicone that is waterproof and sweat-proof.

Step 5: Fit the Band

  • Hold the band with the quick-release lever facing you (the underside).
  • Slide the lever toward the centre of the band to retract the pin, seat one end of the spring bar in a lug hole, then release the lever so the other end clicks into the opposite lug.
  • Give the band a gentle tug. If it moves, the spring bar is not seated — repeat the step.
  • Fit the short piece (with the buckle) on the 12 o'clock side and the long piece (with the holes) on the 6 o'clock side.

Frequently Asked Questions

My lugs measure 20 mm. Will the 22 mm band fit?
No. A band must match the lug width exactly. Our universal bands are made in 22 mm and 24 mm only.

Do the bands attach directly to an Apple Watch?
No. Apple Watch uses its own band connector. Our universal bands fit watches with standard lugs, and they fit the lugs on Catalyst waterproof cases for Apple Watch.

Do I need a spring-bar tool?
No. Every band ships fitted with quick-release spring bars.

Should I measure my wrist flat or around?
Around. The fit ranges above are measured as a closed loop, the way the band sits when worn.

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Conclusion

Three measurements — lug width, spring bar, wrist — and you will have a band that fits first time. Measure the lugs in millimetres, look for the quick-release lever, and wrap the tape around your wrist rather than laying it flat. If you're still unsure, contact us with your measurements and we'll confirm the right size.