The right strap size makes the difference between a watch that sits perfectly on the wrist and one that constantly shifts or pinches. Before you order from JackCoHenry, work through these three measurements.
Quick Reference Table
|
S |
M |
L |
|
|
Long piece |
100mm |
110mm |
120mm |
|
Short piece |
65mm |
75mm |
80mm |
|
Best for wrist |
Under 15cm |
15–19cm |
Over 19cm |
Lug width varies by watch — see Step 1. Custom lengths available on request.
Step 1: Measure Your Lug Width
Lug width is the internal gap between the two lugs on your watch case — the measurement that determines which strap will actually slot in. Use a digital caliper or a millimeter ruler held across the inside edge of the lugs.
JackCoHenry available lug widths: 18mm · 19mm · 20mm · 21mm · 22mm · 24mm
Not sure of yours? Check your watch manufacturer's spec sheet, or contact us and we'll identify it for you.
Step 2: Determine Your Strap Length
There are three ways to find your correct length — pick whichever suits your situation.
Method A: You have an existing two-piece strap on your watch (quickest) — Measure the long piece and the short piece separately, then add them together. Match that total to the closest JackCoHenry size:
-
S = 165mm total (100 + 65)
-
M = 185mm total (110 + 75)
-
L = 200mm total (120 + 80)
If your current strap fits well, this gives you a reliable match. If the current strap doesn't fit ideally, adjust up or down one size accordingly.
Method B: You want a more precise fit (recommended) — This accounts for exactly where your buckle sits, not just the total length.
-
Measure the short piece of your current strap.
-
On the long piece, measure from the lug end to the hole you actually use.
-
Add those two numbers together — this is your "wearing length."
-
Decide which hole you'd prefer to use on your new strap (middle hole is most common). Subtract the distance from the lug to that hole from your wearing length. The result is your ideal short piece length.
-
Match to the S, M, or L short piece lengths above. If none fits exactly, a custom length can be ordered.
Method C: You don't have a strap to measure from (bracelet or new watch) — Measure your bare wrist circumference with a soft tape measure or a strip of paper, then use the size guide in the table above.
Step 3: Choose Your Buckle Width
The buckle width should match the taper (narrow end) of the strap, not the lug end. For most JackCoHenry straps, the taper is 2mm narrower than the lug width — so a 20mm lug strap takes an 18mm buckle, a 22mm takes a 20mm, and so on. The correct buckle width is listed on each product page.
Frequently Asked Questions
Q. What if I'm between sizes?
Size up. A slightly longer strap can always use a different hole; a strap that's too short has no fix.
Q. Can I order a custom length?
Yes. Mention your wrist circumference or your preferred long/short piece lengths when ordering and we'll make it to spec.
Q. Does strap length affect lug width compatibility?
No. Lug width and strap length are independent measurements — choose them separately.
Q. My watch has a bracelet — how do I measure?
Use Method C above: measure your bare wrist circumference and reference the size table.
Read These Next
Got your measurements? Here's what else is worth knowing before you order from JackCoHenry Singapore:
→ Will Your Strap Fit My Watch? — confirm your watch is compatible with a standard aftermarket strap
→ Watch Strap 101 — understand lug width, taper, buckle size, and strap styles
→ How to Change Your Strap — a step-by-step guide to fitting your new strap
Still Unsure? We're Here to Help
If you're not certain which size is right, visit our FAQ for more answers, or contact the JackCoHenry team directly — we're based in Singapore and happy to help you find the perfect fit before you order.