The 38mm straps fit 40mm watches. The Apple Watch Series 4 comes in new sizes (40mm and 44mm instead of 38mm and 42mm), the good news for Apple users is that the old watch bands fit the new sizes. The 38mm and 40mm watches use the same (smaller) strap range. 42 mm and 44 mm watches use the same (larger) straps.
If you want to wear a 42mm or 44mm watch, you'll need a strap. Neither the 40mm nor the 38mm fit. With the apple watch coming in so many different case sizes, it's no wonder people get confused as to which of the different watch bands will fit the watch they have. Solo Loop and Braided Solo Loop bands are only compatible with Apple Watch SE and Apple Watch Series 4 or newer.
In addition to maintaining the same watch band mounting slots, the smaller 38mm and 40mm displays also have smaller screen sizes. The Apple Watch Series 3 has a 38mm screen size, but the 40mm Apple Watch has a slightly larger screen size than the 38mm Apple Watch Series 3, but that's mainly because the screen is much larger. But many of them no longer include options for the 38, 40, 42 and 44 mm size options for all straps. As long as you get the same size for the new Apple Watch, the existing bands should fit seamlessly.
We've combined the new 41mm Solo Loop in English Lavender with the 40mm Series 6 in aluminum (blue), as well as the new Nike Sport Loop 45mm in black with the Apple Watch SE 44mm in black aluminum. However, even though Apple Watch Series 4, 5 and the new Apple Watch Series 6 come in slightly different case sizes of 40mm or 44mm, your old bands from Series 3 and earlier will still fit. If you have an older Apple Watch Series 0, 1, 2 or 3, your straps should be for the 38mm or 42mm case. The Apple Watch Series 7 was one of many announcements made during Apple's “California Streaming” event, sharing the stage alongside the iPhone 13 and 13 Pro, a new iPad Mini with USB-C charging, and more.
For the 40mm and 41mm Apple Watch models, you can get individual loop bands in the size range of one to nine, while the 44mm and 45mm models work with band sizes four through 12.Apple Watches have two screen sizes, 42 mm and 44 mm, but both models have the same mounting slots for the watch bands. This is because when Apple slightly increased the size of the Apple Watch case, they kept the same strap sizes. As for the Apple Watch Series 4, it has been updated to a new size (40 mm and 44 mm instead of 38 mm and 42 mm) and the old watch bands fit the new ones. If the strap is properly installed, it will not slide freely until you hold down the strap release button.
When you buy an Apple Watch band, you may need to specify which watch it is for, large or small, but you can usually get any of the bands for any of the watches.