The Apple Watch began with two simple options, but there are now three different models and four distinct case sizes to choose from. That doesn’t even include the models not officially on sale.
While the band of any Apple Watch is changeable and adjustable, the size of the case itself is crucial to get right before you buy.
If you’re 46mm design has impressed us with its large display, making text easy to read. However, it will be far too big for some people. As a result, it’s essential to note that the smaller case size of the Series models is now a viable option for most people, not just those with petite wrists.
If you’re wondering which size Apple Watch to get, we’ll show you how to measure your wrist and find the perfect fit. This guide also reveals the complete dimensions, weights, and essential details of band compatibility.
Apple Watch sizes explained
Here’s a quick breakdown of the case size available for the Apple Watch, starting with the current generation announced in September 2025 and continuing with older models below.
Current generation:
- Apple Watch Ultra 3 (2025): 49mm
- Apple Watch Series 11 (2025): 42/46mm
- Apple Watch SE 3 (2025): 40/44mm
Discontinued models:
- Apple Watch Series 10 (2024): 42/46mm
- Apple Watch Series 9 (2023): 41/45mm
- Apple Watch Ultra 2 (2023): 49mm
- Apple Watch Series 8 (2022): 41/45mm
- Apple Watch SE 2 (2022): 40/44mm
- Apple Watch Ultra (2022): 49mm
- Apple Watch Series 7 (2021): 41/45mm
- Apple Watch Series 6 (2020): 40/44mm
Explained: Apple’s case size philosophy
Over the years, the Apple Watch has gradually increased in size, now offering 42mm and 46mm options. Consequently, the smallest Series 10/11 matches the size of the original Apple Watch’s largest model. It’s quite astonishing.
The Apple Watch Series 9 retains the 41mm and 45mm case sizes introduced with the Series 7 in 2021, ensuring that older bands remain compatible with the latest smartwatch. Furthermore, 40mm and 44mm bands are also compatible with the new, larger size.
The Apple Watch Series 4, Series 5, and Series 6 models are available in 40mm and 44mm sizes, as are the Apple Watch SE (2020) and SE (2022) models.
- Compare: Apple Watch Series 11 vs. Series 10
You can no longer buy the Series 3 or lower, which used 38mm and 42mm case sizes.
These measurements, we should make clear, denote the size of the bezel; however, the straps also play a role in the specific fit of the smartwatch on your wrist.
As you can see from the breakdown above, Apple’s philosophy is clear; three generation of the Series offer the same case size options, with this then evolved for the new wave. The SE models, meanwhile, have always been based one of these discontinued case designs—typically the last cycle.
The Ultra line is more straightforward. Now three generations in, the premium smartwatch is yet to see any core case size or design changes.
Detailed Apple Watch case sizes and weights
Below, we’ve put the key design specs—dimensions and weight—of the current generation of Apple Watch devices into a table.
| Model | Dimensions (mm) | Weight (GPS) | Weight (GPS + Cellular) | Weight (Titanium) |
|---|---|---|---|---|
| Apple Watch SE 3 (40mm) | 40 x 34 x 10.7 | 26.4g | 27.8g | N/A |
| Apple Watch SE 3 (44mm) | 44 x 38 x 10.7 | 32.9g | 33.0g | N/A |
| Apple Watch Ultra 3 (49mm) | 49 x 44 x 14.4 | 61.4g | N/A | N/A |
| Apple Watch Series 11 (42mm) | 42 x 36 x 9.7 | 30.0g | 29.3g | 34.4g |
| Apple Watch Series 11 (46mm) | 46 x 39 x 9.7 | 36.4g | 35.3g | 41.7g |
Explained: Apple Watch band sizes
There is cross-compatibility between some Apple Watch sizes and models, as well as different bands. However, the operative word there is ‘some’—and you’ll need to understand a few crucial rules if you’re to use old bands on a new device (or vice versa).
- Band sizes for 38mm, 40mm, and 41mm Apple Watch cases are interchangeable
- Apple Watch straps for 42 mm, 44 mm, 45 mm, and 46 mm case sizes also all work together
- All 44mm, 45mm, and 46mm straps will all work with the 49mm Apple Watch Ultra/Ultra 2
For the first time, the Apple Watch Series 10 offers both small and large options with the same strap size. You can also use ‘regular’ Apple Watch bands on the Ultra model.
These rules should apply to third-party options, too, but read reviews for your specific Apple Watch device before you purchase.
- Compare: Apple Watch Ultra 2 vs. Ultra 3
Sizing Apple’s ‘Solo Loop’ bands
Note that certain models require you to choose a size at purchase. For example, Sport bands come with both S/M and M/L strap options to select from.
The Apple Solo Loop bands come in a variety of sizes, and Apple provides a tool to help you measure your wrist accurately, allowing you to choose the correct size. That’s crucial — and take it from our experience, you don’t want to get this wrong.
We also recommend using a proper tape measure. If it’s a bit loose, obtaining accurate health data could be a challenge.
How to measure your wrist for the Apple Watch
The fit of your watch is somewhat subjective, but it’s essential to know the size of your wrist before purchasing the Apple Watch or an additional band.
So, how can you be certain? Well, grab a flexible tape measure and measure that wrist.
Place the strip just below your wrist bone and around the area where you typically wear the band. Wrap it around your wrist and align it with the sizes of your watch model.
Generally speaking, a small wrist measures 5 to 6.5 inches, while a large wrist ranges from 7 to 8.5 inches. However, a key benefit of many Apple Watch bands is that they can be adjusted using Velcro or the perforations in sports straps to achieve a precise fit.
Just don’t go too tight or too loose. While it can become uncomfortable, it also impacts the accuracy of the Apple Watch’s heart rate monitor.
