Watch Lug Width & Strap Compatibility Finder
Look up a supported watch reference or measure the gap yourself. Find the watch-end width to investigate, compare a strap, and check which attachment details still need to match.
Choose your exact reference or enter a measurement to see a width and attachment checklist.
Browse the 5 sourced references
Hamilton Khaki Field Mechanical 38mm · H69439931
20 mm listed lug width · Conventional lugs — other fit checks still required
Hamilton lists a 20 mm lug width. The 38 mm case size and 47 mm lug-to-lug measurement are different dimensions.
Manufacturer source · Checked 2026-10-09Seiko 5 Sports SRPE55 · SRPE55
20 mm listed lug width · Conventional lugs — other fit checks still required
Seiko lists 20 mm between the lugs. A bracelet's fitted end links still need to match the case.
Manufacturer source · Checked 2026-10-09Seiko 5 Sports SRPD55 · SRPD55
22 mm listed lug width · Conventional lugs — other fit checks still required
Seiko lists 22 mm between the lugs. Do not substitute the 42.5 mm case diameter or 46 mm lug-to-lug length.
Manufacturer source · Checked 2026-10-09Tissot Everytime 34mm · T143.210.11.011.01
16 mm listed lug width · Conventional lugs — other fit checks still required
Tissot lists a 16 mm lug width and a quick-release bracelet. Quick release does not guarantee that another bracelet's end links will fit.
Manufacturer source · Checked 2026-10-09Tissot PRX Quartz 40mm · T137.410.11.091.00
12 mm listed lug width · Integrated attachment — model-specific fit required
Tissot lists 12 mm and describes an integrated case and bracelet. That number is not a recommendation for a generic 12 mm strap. Use a strap explicitly designed for this PRX case and reference.
Manufacturer source · Checked 2026-10-09
Measure lug width at the attachment
Lug width is the inside gap where the strap joins the watch. Measure between the inner faces of the lugs at that point using a millimetre ruler or calipers, protecting the case from scratches. If the strap hides the gap or removal is unfamiliar, ask a watchmaker to measure it.
Case diameter measures across the watch body. Lug-to-lug measures along the case from one set of lugs to the other. Neither tells you the strap width. The buckle-end width may also be smaller than the watch-end width because straps can taper.
Match the exact reference
This finder includes five references from Hamilton, Seiko and Tissot. Each entry links to the manufacturer's specification and shows when it was checked. A shared collection name, similar appearance or case diameter does not establish an identical lug width. Modified cases and aftermarket adapters may differ from the original specification.
If your reference is missing, use the measurement option. The finder does not infer a model or fill gaps with an estimated width. Inch measurements are converted using 25.4 millimetres per inch; the tool does not round them to the nearest strap size.
Width is only one part of strap compatibility
- Conventional lugs: compare watch-end width, spring-bar dimensions, hole position and clearance. A straight-end strap is a starting point for checking fit.
- Fixed bars: a conventional closed-end two-piece strap cannot pass over a fixed bar. Check a suitable pass-through or open-ended construction and its clearance.
- Integrated bracelets and proprietary connectors: use a compatibility statement for the exact reference. A listed lug width does not make a generic strap interchangeable.
- Curved ends and fitted bracelet end links: the case profile and attachment geometry must match too. Quick release describes how a bar is removed; it does not establish universal fit.
- Wrist fit: choose strap length separately and check buckle or clasp dimensions if reusing hardware. Do not force an oversized strap between the lugs.
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Frequently Asked Questions
How do I find my watch lug width?
Select your exact reference if it is in the sourced list. Otherwise measure the inside gap at the strap attachment and use the manual option. Check the manufacturer's documentation where available, especially for integrated bracelets or modified watches.
Is lug width the same as case size or lug-to-lug?
No. Lug width is the gap for the strap, case size measures the watch body, and lug-to-lug measures the length of the case including the lugs. For example, Seiko lists a 20 mm lug width for SRPE55 despite its 40 mm case diameter and 44.6 mm lug-to-lug measurement.
Can I fit a 20 mm strap in 19 mm lugs?
Do not assume it will fit or squeeze it into place. This finder reports a width mismatch. Recheck the gap and choose the specified watch-end width, then confirm spring bars, end shape and clearance.
Does a matching width guarantee that a bracelet fits?
No. Matching width is only a preliminary check. Fitted end links, spring-bar tips and holes, clearance, proprietary connectors and case shape can prevent a bracelet or strap from fitting even when the width is the same.
Why does the Tissot PRX result not suggest a generic 12 mm strap?
Tissot lists 12 mm for the included PRX reference, but it also describes an integrated case and bracelet. That connection requires a model-specific fit. Use Tissot's compatible strap guidance and confirm the exact case size and reference instead of buying a generic strap by that number alone.
What if my watch or attachment is not listed?
Use your measurements and choose the attachment type. If you are unsure, the result will ask you to identify the connection before choosing a strap. The catalog contains five exact references and does not claim to cover other variants.
Does this tool upload measurements or scan a photo?
No. Lug-width lookup, unit conversion and comparison run in your browser. The tool does not send the entered measurements with engagement analytics. Use the separate Find This Watch photo tool if you need identification leads.
Need help identifying the watch?
Use Watchsy for photo-based watch research, then confirm the exact reference before choosing a strap.
