2026-06-10
Watch Strap Sizing Guide — Lug Width, Length & Buckle Size
Watch Strap Sizing Guide
A watch strap has multiple dimensions — and getting each one right is what separates a strap that fits perfectly from one that looks wrong regardless of its quality. This guide explains every measurement, what each one means, and how to get it right.
The Four Key Measurements
1. Lug Width — the most important measurement. The gap in millimetres between the two lugs on your watch case. Must match the strap width exactly. See how to measure lug width.
2. Strap Length — determines whether the strap fits your wrist. Standard or short. See do I need a short strap.
3. Taper Width — many straps taper from a wider lug end to a narrower buckle end. The listed width is always the lug end.
4. Buckle Width — the width of the buckle bar. Should match the strap's buckle end width for a clean fit.
Lug Width — Standard Sizes
| Lug Width | Common Watches |
|---|---|
| 14mm | Small vintage dress, ladies' classics |
| 16mm | Michele, Cartier Tank ladies', ladies' dress |
| 17mm | Cartier Tank Solo, vintage dress |
| 18mm | Nomos, Junghans, ladies' sport, slim dress |
| 19mm | Vintage Rolex, Datejust 36mm vintage |
| 20mm | Omega Seamaster, Seiko SKX, Tudor Black Bay, Rolex Sub — most common |
| 21mm | Rolex Oyster Perpetual 36mm, Datejust 36mm |
| 22mm | Tudor Pelagos, IWC Pilot's Watch, Marathon GSAR |
| 23mm | Blancpain Fifty Fathoms 45mm |
| 24mm | Panerai Luminor |
For a complete reference by model see the lug width by watch model guide.
Strap Length — Standard vs Short
| Long piece | Short piece | Suits wrist | |
|---|---|---|---|
| Standard | ~115mm | ~75mm | 165-210mm (6.5-8.3 inches) |
| Short | ~105mm | ~65mm | 140-165mm (5.5-6.5 inches) |
If your wrist circumference is under 165mm (6.5 inches), order a short strap. See short watch straps.
Taper Width
A tapered strap is wider at the lug end and narrower at the buckle end. Common taper examples:
| Lug width | Buckle end | Character |
|---|---|---|
| 22mm | 20mm | Subtle — suits most cases |
| 20mm | 18mm | Standard taper for sport watches |
| 18mm | 16mm | Suits dress and slim cases |
A straight (non-tapered) strap maintains the same width throughout. Straight straps suit watches with prominent, widely spaced lugs. Tapered straps suit most standard cases.
Buckle Width
The buckle pin bar width should match the narrower (buckle) end of the strap — not the lug end width. A 20mm strap that tapers to 18mm at the buckle end uses an 18mm buckle. Using a wider buckle creates visible overhang and looks wrong.
CNS buckles are sized to match each strap's taper specification — no calculation required.
Thickness
Strap thickness affects how the strap sits in the lug gap and how it feels against the wrist.
Standard thickness (2.5-3.5mm) — suits most watches with standard lug clearance.
Padded (4-6mm) — raised profile for larger sport watches. May not fit watches with very tight lug clearance.
Slim (1.5-2mm) — for dress watches and watches with minimal lug clearance. Perlon and non-stitch calfskin are the slimmest options.
Frequently Asked Questions
What does 20/18mm mean on a watch strap? The first number (20mm) is the lug end width — the end that attaches to the watch. The second number (18mm) is the buckle end width after taper. Order using the first number — 20mm matches 20mm lugs.
What is standard strap length? A standard strap long piece is approximately 115mm, short piece approximately 75mm — sized for a wrist of 165-185mm (6.5-7.3 inches). See short watch straps for smaller wrists.
Does strap thickness matter? It matters if your watch has tight lug clearance — a padded strap may not fit cleanly between very close lugs. For most watches standard thickness fits without issue.
Find your size: 16mm | 18mm | 19mm | 20mm | 21mm | 22mm | 23mm | 24mm