A new strap is the cheapest way to make a watch feel new again, but only if it fits. This watch strap size finder gives you the lug width for 40 popular watches, shows you how to measure any other watch, and suggests the strap types that suit how and where you wear it.
Find the right strap size
Get your lug width, then the strap types that suit how you wear the watch.
Step 1 · Your lug width
Pick the width in millimetres.
- Take the strap off, or look at the end where it meets the case.
- Measure the inside gap between the two lugs (red line) with a ruler or calipers.
- Round to the nearest whole millimetre. Most watches use an even number: 18, 20 or 22.
Step 2 · How you wear it
Step 3 · Wrist size
Lug width chart
The numbers below are the same ones the tool uses. Where two or more sources agree, or the maker publishes the size, we mark it as confirmed. Single-source sizes are worth a quick check with a ruler before you order.
| Watch | Lug width | Confidence |
|---|---|---|
| Seiko SKX007 / SKX009 / SKX173 | 22 mm | 2+ sources / maker |
| Seiko SKX013 / SKX023 | 20 mm | 2+ sources / maker |
| Seiko 5 SNK809 / SNK803 / SNK805 / SNK807 | 18 mm | 2+ sources / maker |
| Seiko 5 SNKL series | 18 mm | 1 source |
| Seiko 5 SNXS79 / SNXS73 / SNXS77 | 19 mm | 1 source |
| Seiko 5 Sports SRPD (42.5 mm) | 22 mm | 2+ sources / maker |
| Seiko 5 SNZF17 ‘Sea Urchin’ | 22 mm | 2+ sources / maker |
| Seiko Prospex Turtle (SRP777, SRPE93, SRPC91) | 22 mm | 2+ sources / maker |
| Seiko Prospex Samurai | 22 mm | 2+ sources / maker |
| Seiko Prospex Mini Turtle | 20 mm | 2+ sources / maker |
| Seiko Monster (SKX779 / SKX781) | 20 mm | 2+ sources / maker |
| Seiko Sumo (SBDC001 / SPB101) | 20 mm | 2+ sources / maker |
| Seiko Alpinist (SARB017 / SPB121 / SPB155) | 20 mm | 2+ sources / maker |
| Seiko SARB033 / SARB035 | 20 mm | 2+ sources / maker |
| Seiko Presage Cocktail Time (SRPB41 / SRPB43) | 20 mm | 2+ sources / maker |
| Seiko Prospex 62MAS reissue (SPB143 / SPB147) | 20 mm | 2+ sources / maker |
| Seiko Flightmaster (SNA411 / SNA413) | 21 mm | 2+ sources / maker |
| Seiko Tuna (SBBN013 / SBBN039) | 22 mm | 1 source |
| Seiko SSB479 chronograph | 20 mm | 1 source |
| Vintage Seiko 6309 Turtle | 22 mm | 1 source |
| Vintage Seiko 7002 diver | 22 mm | 2+ sources / maker |
| Vintage Seiko 6139 ‘Pogue’ | 19 mm | 1 source |
| Vintage Seiko 6138 ‘Bullhead’ | 20 mm | 1 source |
| Vintage Seiko 7548 quartz diver | 22 mm | 1 source |
| Vintage Seiko 7A28 chronograph | 20 mm | 1 source |
| Vintage Seiko 6117 World Time | 20 mm | 1 source |
| Casio Duro MDV106 | 22 mm | 2+ sources / maker |
| Casio A168 / A158 | 18 mm | 1 source |
| Casio F-91W | 18 mm | 1 source |
| Casio G-Shock DW-5600 | Special fitting | 1 source |
| Orient Bambino | 21 mm | 2+ sources / maker |
| Timex Weekender 38 mm | 20 mm | 2+ sources / maker |
| Hamilton Khaki Field Mechanical 38 mm | 20 mm | 1 source |
| Citizen Promaster Diver (BN0150 / BN0151) | 20 mm | 1 source |
| Tissot PRX 40 mm | Special fitting | 1 source |
| Invicta Pro Diver 8926OB | 20 mm | 1 source |
| Bulova 96A135 Sutton | 22 mm | 1 source |
| Vostok Amphibia | 18 mm | 1 source |
| Omega Speedmaster Professional | 20 mm | 1 source |
| Tudor Black Bay 58 | 20 mm | 1 source |
How to measure lug width
Remove the strap, or look closely at where it meets the case. Measure the inside gap between the two lugs with a ruler or a pair of calipers, then round to the nearest whole millimetre. Do not measure the old strap at the buckle end. Most straps taper, so the buckle end is narrower than the lug end.
Which strap type should you choose?
- Leather for office and dress wear. Keep it away from water and heavy sweat.
- FKM rubber for heat, swimming and sport. It is softer and less sticky than cheap silicone.
- NATO and nylon for travel and everyday wear. Washable, cheap and quick to dry.
- Steel bracelet for one-strap-for-everything wearers. Check the end-link shape so it sits flush with the case.
- Tropic rubber or beads-of-rice bracelets for the vintage diver look on a 6309 Turtle, an SKX or a modern Turtle.
Our Casio Duro review covers why a 22 mm rubber strap suits a budget diver, and the Seiko SSB479 review shows how a 20 mm leather strap changes the look of a small chronograph.
More free tools
Buying a vintage Seiko? Check that its caseback numbers belong together with our Seiko Franken Checker. Shopping for someone else? Try the Watch Gift Finder. And once the collection grows, a lined box keeps straps and watches from scratching each other. See our Rothwell watch box review.
Frequently asked questions
What size strap does my watch need?
Your strap width must match the lug width: the inside gap between the two lugs where the strap attaches. Search your model in the tool above, or measure the gap with a ruler and round to the nearest millimetre. Most men’s watches use 18, 20 or 22 mm.
Can I put a 20 mm strap on a 22 mm watch?
It will fit, but it leaves a 1 mm gap on each side that looks loose and lets the strap slide on the spring bar. Going the other way, a 22 mm strap will not fit into 20 mm lugs at all. Always buy the exact width.
What is the best watch strap for hot and humid weather?
FKM rubber or a nylon NATO. Both shrug off sweat, dry quickly and do not smell. Leather is the worst choice for daily wear in tropical heat, because sweat breaks it down fast.
What does quick release mean on a watch strap?
Quick-release straps have a small lever on each spring bar, so you can pull it back with a fingernail and swap the strap in seconds without tools. If you change straps often, it is worth paying for.
Why does my Seiko have an odd lug width like 19 or 21 mm?
Some Seiko 5 models (the SNXS series) use 19 mm, and the Flightmaster and Orient Bambino use 21 mm. Odd sizes are harder to shop for, so search the exact number. A strap one size off will either not fit or leave a gap.