How to measure a watch strap
Every point, drawn on the garment so there is no guessing where the tape goes.
Quick answer
A watch strap needs six numbers: length, two half-lengths (length 1, length 2), then width at the lugs and two taper widths (width 1, width 2). Length leads because it sets wrist fit, taken straight along the band, not around. Hover or tap each step on the diagram to see where the ruler sits. Sizely keeps all six together.
A buyer matching your strap to their watch checks total length against their wrist first, then the lug width that has to seat between the watch lugs. Get the lug width wrong and the strap will not fit the case at all. Generic listings give one length and one width; this page draws every run on the strap so both the wrist and the case are covered before anyone buys.
- A
Length
The total length of both pieces laid end to end, from the tip of the buckle side to the tip of the holed side, not counting the case gap. This sets overall wrist fit, so it leads. Hover or tap this step to see where the line starts and ends.Recorded as-is, measured along the strap. Do not double.
- B
Length 1
The longer half, usually the side with the holes that feeds through the buckle. Read it from the lug end to the tip so a buyer knows how much band passes around the wrist.Recorded as-is, a single end-to-end run. Do not double.
- C
Length 2
The shorter half, the side that carries the buckle. Measured from its lug end to the buckle, it tells the buyer how the two pieces split around the wrist.Recorded as-is, a single end-to-end run. Do not double.
- D
Width
The lug width, taken across the strap at the end that seats between the watch lugs. This is the number that has to match the watch case, so a buyer checks it before anything else about fit.Recorded as-is, measured straight across. Do not double.
- E
Width 1
The width partway down the strap, where many bands begin to taper. Reading it shows how quickly the strap narrows from the lugs toward the buckle.Recorded as-is, measured straight across. Do not double.
- F
Width 2
The buckle-end width, taken across the narrowest point near the clasp. Together with the lug width it describes the full taper of the strap.Recorded as-is, measured straight across. Do not double.
Lay the strap flat on a table and read it relaxed, never bent around a wrist or pulled tight. A strap is small, so work in millimeters and read to the nearest one. Every number here is linear: total length and the two half-lengths run end to end along the band, and the three widths run straight across it. Nothing doubles, because you measure the strap as it lies, not as a folded loop.
Watch strap size reference
| Size | Length | Length 1 | Length 2 | Width |
|---|---|---|---|---|
| S | 6.7 | 4.7 | 2.95 | 0.71 |
| M | 7.1 | 4.9 | 3.15 | 0.79 |
| L | 7.5 | 5.1 | 3.35 | 0.87 |
| XL | 7.9 | 5.3 | 3.5 | 0.94 |
| 2XL | 8.3 | 5.5 | 3.7 | 1.02 |
Frequently asked
What size watch strap do I need?
Measure your wrist circumference with a flexible tape, then pick a strap whose total length covers your wrist plus enough overlap to reach a middle buckle hole. A 7 inch wrist usually pairs with a strap around 7.5 inches total. Just as important, match the lug width to your watch, since a 20 mm case needs a 20 mm strap end.
How do I know what lug width my watch needs?
Measure the gap between the two lugs where the strap seats, straight across in millimeters. Common sizes are even numbers like 18, 20 and 22 mm. The strap's lug-end width, listed here as the main width, has to equal that gap or the spring bar will not hold the strap in place.
Do I measure a watch strap around the wrist or flat?
Flat. Lay both pieces end to end on a table and read the total length straight along the band, then read each half and each width across the strap. You do not wrap it or double any number, because a strap is a flat object measured as it lies, unlike a closed bracelet loop.
Should I measure a watch strap in inches or millimeters?
Millimeters, especially for the lug width and the taper, since strap fittings are sold in even millimeter steps and a single millimeter decides whether the strap seats. Lengths can be shown in inches too for buyers who think that way, as long as you label the unit on each field.
Why do two straps of the same length fit my wrist differently?
Thickness, stiffness and where the buckle sits all change the effective fit of one length. A thick padded strap eats overlap and feels shorter, while a thin supple one wraps closer. Listing both half-lengths and the widths lets a buyer judge the real fit against a strap they already wear.
Related size charts & tools
How to measure a braceletSources: Sizely garment engine, spec #374 (Classic Watch Strap), total length, two half-lengths and three widths. Last verified June 2026.
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