Apple Watch Size (mm)
Series 1, 2, 3 - 38mm or 42mm
Series 4, 5, 6, SE - 40mm or 44mm
Series 7, 8 - 41mm or 45mm
Ultra - 49mm
How do I find out my watch size?
Step1: Take your Apple watch off your wrist, and turn it over to the underside.
Step2: the top right of the Apple watch displays what size your Apple Watch is in millimetres (mm)
38mm / 40mm / 41mm Apple Watch
fits 130mm-230mm wrists
42mm / 44mm / 45mm Apple Watch
fits 135mm-255mm wrists
How to measure your wrist?
All you need is a tape measure and your wrist, of course!
Step 1: Use the millimetre (mm) side of the tape measure
Step 2: Wrap the tape measure around your wrist
Step 3: Now that the tape measure has met the beginning, sign up the 0mm with your wrist circumference in mm
Step 4: There is your wrist size! Use this to shop in each strap's size range.