1. What’s the difference between 42 and 44 Apple Watch?
2. Can I use a 40mm band on a 42mm watch?
3. Will a 40mm Apple Watch band fit a 42mm Apple Watch?

What’s the difference between 42 and 44 Apple Watch?

The smaller of the two Apple Watch sizes has a height of 40mm, the larger, 44mm. Even if you think you want to go small, you can still consider both sizes — neither is enormous — though those with smaller wrists may find the 40mm fits more comfortably on the wrist.

Can I use a 40mm band on a 42mm watch?

Answer: A: No. 40mm bands will fit 38mm Series 3 and earlier, 44mm bands will fit 42mm Series 3 and earlier.

Will a 40mm Apple Watch band fit a 42mm Apple Watch?

Answer: A: You can match this band with any Apple Watch Series 4 case of the same size. It also works with all previous versions of Apple Watch, including Apple Watch Series 3. The 40mm band works with the 38mm case, the 44mm band works with the 42mm case.