Guide
Apple Watch Band Size Guide
Apple Watch bands don't come in one size per watch. They come in two families, small and large, and any band in the right family fits. Here's which family your watch is in, and the one size number Apple reused that catches people out.
The two Apple Watch band families
| Band family | Case sizes | Watches |
|---|---|---|
| Small | 38, 40, 41, 42mm* | 38mm (Series 1–3), Apple Watch 40mm, Apple Watch 41mm, Apple Watch 42mm (Series 10/11) |
| Large | 42mm†, 44, 45, 46, 49mm | 42mm (Series 1–3), Apple Watch 44mm, Apple Watch 45mm, Apple Watch 46mm, Apple Watch Ultra 49mm |
* 42mm Series 10 and 11 only. † 42mm Series 1–3 only.
Apple's support page puts it simply: bands for 38, 40 and 41mm cases are compatible with each other; bands for 42 (the original Apple Watch), 44 and 45mm cases are compatible with each other; and 46mm and 49mm bands fit 44–46mm cases. So a band from a 40mm Apple Watch SE fits a 41mm Series 9, and a 45mm band fits a 44mm watch.
The 42mm trap
Apple has used “42mm” for two different sizes. The first Apple Watch (Series 1–3) came in 38mm and 42mm, and its 42mm was the large size. The Series 10 and 11 come in 42mm and 46mm, and their 42mm is the small size. So an old 42mm band won't suit a new 42mm watch. Go by the family, not the number: a 42mm Series 10 takes 38/40/41mm bands (see the Apple Watch 42mm (Series 10/11) page).
Apple Watch Ultra
The Ultra's 49mm bands (Ocean Band, Alpine Loop, Trail Loop) are made for it, and Apple says 44, 45 and 46mm bands also fit the Ultra, though it recommends them for casual, everyday use. Ultra bands also fit 44–46mm watches. If you wear a Solo Loop on an Ultra, you may need a smaller loop size than on a smaller watch, because the bigger case takes up more of your wrist.
How to find your case size
The case size is part of the product name on the box and your receipt (for example “Series 9, 45mm”). If you don't have either, measure the case from top to bottom, not side to side: that height is the case size. Then match it to the family above.
Solo Loops are sized twice
Stretchy Solo Loops and Braided Solo Loops have no buckle, so they come in numbered wrist sizes as well as the small or large family. Get both right: the family for your case, and the loop size for your wrist, which Apple's printable band sizing tool helps with.
How to change an Apple Watch band
Every Apple Watch band uses the same slot, so you don't need tools. These steps follow Apple's own guide, Change your Apple Watch strap.
- Lay the watch face down on something soft and clean, such as a microfibre cloth.
- Press and hold the band release button for the band you're removing.
- Keep holding it and slide the band sideways out of the slot. If it won't move, press the button again and hold it down for the whole slide.
- Turn the new band so its printed text faces you, then slide it in until you feel and hear a click.
- Check it: a fitted band shouldn't slide unless you hold the release button.
Bands with an extra step:
- Link Bracelet: split it in two before taking it off the watch. Close the butterfly clasp, hold one of the quick-release buttons on the inside of the bracelet and gently pull the links apart. Then remove each half as above. Don't force or twist it.
- Ocean Band, Alpine Loop and Trail Loop: line the connector up parallel with the case and push it in gently, with the metal tooth facing down.
- Solo Loop and Braided Solo Loop: they change the same way, but have no buckle. To put one on or take it off, pull the bottom of the band to stretch it over your wrist.
- Milanese Loop: versions from 2018 onwards open fully, so the magnet slides through the connector. Older ones don't.
If it won't click in: never force it. Slide the band left, then right. If it still won't lock, centre it, push it home and wiggle it gently up and down. Don't wear the watch while the band can slide. For ordinary watches with spring bars, see how to change a watch strap.
Third-party bands and adapters
- Check the listing names your case size or family. Most list several sizes, such as “41/40/38mm” or “45/44/42mm”.
- Connector quality varies. A loose connector rattles; a tight one is hard to slide in. Reviews are the best guide.
- To use an ordinary watch strap, fit adapters that slide into the band slot and give a standard spring-bar lug width. Check which width they give before buying straps.
Every Apple Watch in our index: Apple Watch 45mm, Apple Watch 41mm, Apple Watch Ultra 49mm, Apple Watch 46mm, Apple Watch 42mm (Series 10/11), Apple Watch 44mm, Apple Watch 40mm.