Watch band size from your wrist.

Worked example

A 17 cm wrist is 6.69 in around. 17 cm falls in the 16 to 19 cm band, so a standard strap suits. In millimetres it is 170 mm, inside both Apple ranges for 38 to 42 mm cases (S/M 130 to 180 mm and M/L 150 to 200 mm), so either Sport Band size works: S/M for snug, M/L for loose. A 38 to 41 mm case is the usual range for that wrist.

How it works

Apple Sport Band. For 38, 40, 41 and 42 mm cases Apple lists S/M for wrists of 130 to 180 mm and M/L for 150 to 200 mm. Apple publishes different, larger ranges for 44 mm and bigger cases, so for a big case check Apple's band size guide instead of this result. Below 150 mm only S/M fits and above 180 mm only M/L fits. Between them, pick by how snug you like it.

Strap length classes are common watch-retail guidance: short for wrists of about 13 to 16 cm, standard 16 to 19 cm, long 19 to 23 cm. The case diameter bands (for example 38 to 41 mm for a 16 to 18 cm wrist) are the usual look-right ranges, not a standard. A wide, flat wrist can carry a larger case than a narrow, round one.

Strap makers publish their own length charts, and straps from different brands differ by several millimetres. Use the maker's chart when buying a specific strap.

Sources and basis (checked 2026-10-05):

• Apple Support, Find your Apple Watch band size: Sport Band S/M 130 to 180 mm and M/L 150 to 200 mm wrists, for 38 to 42 mm cases. Checked 2026-10-05.
• Strap lengths and case sizes: common watch retail guidance, not a published standard.

FAQ

What size watch band do I need for a 7 inch wrist?

A 7 in wrist is 17.8 cm, which suits a standard length strap and either Apple Sport Band size (38 to 42 mm cases).

How do I measure my wrist for a watch?

Wrap a soft tape or a paper strip around the wrist just above the wrist bone, where the watch sits, snug but not tight, and read the circumference.

What size watch looks right on a small wrist?

Wrists of 14 to 16 cm usually suit 34 to 38 mm cases. Lug-to-lug distance matters too: it should not overhang the wrist.

Are watch strap sizes standard?

No. Short, standard and long are loose classes and each maker sets its own lengths, so check the strap's listed length.

What is the difference between band size and lug width?

Band size is the length for your wrist. Lug width, in mm, is the strap width that fits the watch and is set by the watch, not your wrist.