While the band of any Apple Watch is changeable and adjustable, the size of the case itself is crucial to get right before purchasing.

Here’s the breakdown of the case sizes in each modern Apple Watch generation:

• Apple Watch Series 10 (2024) – 42/46mm

• Apple Watch Ultra (2022)/Ultra 2 (2023) – 49mm

• Apple Watch SE 2 (2022) – 40/44mm

• Apple Watch Series 9 (2023) – 41/45mm

• Apple Watch Series 8 (2022) – 41/45mm

• Apple Watch Series 7 (2021) – 41/45mm

• Apple Watch Series 6 (2020) – 40/44mm

Here are more data to identify your apple watch from apple.com