The right replacement strap is chosen by lug width, not by the watch's case diameter. Measure the opening where the strap attaches, record the result in millimetres, and then choose a strap with the same attachment width. That simple check prevents the most common sizing mistake: ordering a strap that looks close in a product photo but cannot seat correctly between the lugs.
What watch strap width means
Watch strap width is the distance across the strap at the watch end. Lug width is the matching distance between the inside faces of the watch lugs. A 40mm watch can use a 20mm strap, a 22mm strap, or another size entirely. The number in the case-size description does not tell you which strap to buy.
DailyTime's Watch Strap Size Guide recommends measuring between the inside edges of the lugs in millimetres. Write down the measured number before you compare listings. The strap width should match that measurement; a mismatch can leave a visible gap or prevent the spring bar from seating properly.
How to measure lug width at home
- Remove the existing strap if it hides the lug opening. Use a spring-bar tool carefully so you do not scratch the case.
- Measure the clear distance between the inside faces of the lugs with a ruler marked in millimetres or a digital caliper.
- Measure the watch itself, rather than the old strap. A stretched or incorrectly labelled strap is not reliable evidence.
- Record the result and compare it with the product's stated attachment width. If the measurement falls between sizes, do not force a larger strap into the opening.
For a first recommendation based on measured lug width and wrist circumference, use the Watch Strap Size Calculator. It is a starting point. Curved lugs, limited spring-bar clearance, thick end links, keepers and personal wearing preference can still affect the final fit.
Choosing between common strap widths
20mm straps
Twenty millimetres is a common size for compact and mid-size watches. DailyTime's Striped Leather Watch Strap has 20mm and 22mm attachment options. Its product record tells shoppers to measure the space between the lugs before selecting the size, which is the right order of operations.
22mm straps
Twenty-two millimetres is common on sport, field and larger everyday watches. Choose it only when the lug opening measures 22mm. Case diameter, wrist circumference and visual preference cannot replace that measurement. If a strap is listed in both 20mm and 22mm, treat those as separate fit options, not as interchangeable lengths.
24mm straps
Twenty-four millimetres appears on wider cases and heavier-looking watches. DailyTime's Twin-Ridge Leather Watch Strap is offered in 20mm, 22mm and 24mm attachment widths. Its listing also makes the key distinction explicit: strap width is measured at the watch, not across the case.
Check more than the width
Matching the millimetre number is necessary, but it may not be sufficient. Check the product page for the strap material, thickness, buckle style and available length. A thick strap can sit differently under tight lugs, and a curved or fixed-bar case may need a specially shaped option. Confirm that the spring bar can pass through the strap and still reach both lug holes.
Spring-bar diameter and shoulder shape also matter when replacing hardware. DailyTime's compatibility guidance keeps unverified dimensions marked as unknown, so do not infer fit from a similar-looking watch or from the movement name. If the watch has unusual lugs, fixed bars or very little clearance, contact support with the model reference and your measured dimensions before ordering.
Strap length and comfort
Width determines whether the strap fits between the lugs; length determines where the buckle sits on your wrist. Measure around the wrist where the watch will sit, then compare that measurement with the product's short, regular or long options when listed. Padding, keeper placement and the number of adjustment holes can change the feel even when two straps share the same width. A longer strap is not automatically better, especially if the tail extends far beyond the keeper.
Color and material are the final decisions after fit is confirmed. Leather can change character with wear, while a steel or synthetic option may suit a wetter routine. Treat those as comfort and style choices after the lug measurement, width, length and hardware have been checked.
A quick buying checklist
- Measure the inside lug width in millimetres.
- Choose the same attachment width on the strap listing.
- Check strap length against your wrist circumference and the published size options.
- Review thickness, buckle finish and spring-bar clearance.
- Confirm unusual or unverified dimensions before purchase.
Once you have the measurement, browse DailyTime's watch strap collection. Compare the available width, material, length and color options, then choose the variant that matches your recorded lug width. A measured fit gives you a much better starting point than choosing by case diameter alone.
Browse Watch Straps when you are ready to compare current sizes.