Apple
Watch SE 3 - GPS · 40mm vs Watch Series 9 - GPS · Aluminium · 41mm
Size, specs & wrist fit compared
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Which one fits you
Both need much the same wrist — roughly 42–59mm across the flat of the wrist. Neither will fit where the other won't, so decide on thickness, weight and features instead.
The Watch Series 9 - GPS · Aluminium · 41mm wears larger than the Watch SE 3 - GPS · 40mm (35mm vs 34mm case), giving it more wrist presence — and needing a wider wrist to sit cleanly.
On the wrist the Watch SE 3 - GPS · 40mm feels lighter (26.3g vs 32g, case only).
Both are middle-of-the-pack for thickness among the 34mm and 35mm watches in the database.
The Watch Series 9 - GPS · Aluminium · 41mm is 1mm wider, 1mm longer and 5.7g heavier than the Watch SE 3 - GPS · 40mm. Both are rectangle.
Watch SE 3 - GPS · 40mm
Watch Series 9 - GPS · Aluminium · 41mm
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Apple
Watch SE 3 - GPS · 40mm
Apple
Watch Series 9 - GPS · Aluminium · 41mm
2D Dimension Schematics
Every case drawn to scale on a shared centre — from above, and in profile against the wrist.
- Apple Watch SE 3 - GPS · 40mm34mm × 40mm · 10.7mm thick
- Apple Watch Series 9 - GPS · Aluminium · 41mm35mm × 41mm · 10.7mm thick
3D preview
Watch SE 3 - GPS · 40mm vs Watch Series 9 - GPS · Aluminium · 41mm on a wrist
Sized to your own wrist, turned any way you like.
Shapes are built from published measurements, not manufacturer 3D models — accurate proportions, generic dial.
Battery life compared
Runtime for every power mode either watch publishes, 2 of them directly comparable.
SE 3 - GPS · 40mmSeries 9 - GPS · Aluminium · 41mm
Battery Saver
32 hours36 hoursSmartwatch
0.75 days0.75 days
Specifications
The short version
11 key specs| Spec | AppleWatch SE 3 - GPS · 40mm | AppleWatch Series 9 - GPS · Aluminium · 41mm |
|---|---|---|
| Case Width | 34mm | 35mm |
| Lug-to-Lug | 40mm | 41mm |
| Thickness | 10.74mm | 10.7mm |
| Weight | 26.3g | 32g |
| Shape | Rectangle | Rectangle |
| Water Resistance | 5 ATM | Waterproof |
| GPS | Yes | Yes |
| Display type | OLED/AMOLED | OLED/AMOLED |
| Screen size | 1.57 inches | 1.69 inches |
| Battery life | 0.75 days | 0.75 days |
| Released | 2025 | 2023 |
Every specification
115 specs| Spec | Apple Watch SE 3 - GPS · 40mm | Apple Watch Series 9 - GPS · Aluminium · 41mm |
|---|---|---|
| Design | ||
| width | 34 | 35 |
| height | 40 | 41 |
| volume | 14.61 cm³ | 15.35 cm³ |
| weight | 26.3 g | 32 g |
| thickness | 10.74 | 10.7 |
| ATM rating | 5 ATM | — |
| resolution | 324 x 394 px | 352 x 430 px |
| screen size | 1.57 inches | 1.69 inches |
| Display type | OLED/AMOLED | OLED/AMOLED |
| Has a display | Yes | Yes |
| pixel density | 325 ppi | 329 ppi |
| maximum altitude | 10000 feet | — |
| water resistance | Waterproof | Waterproof |
| Always-On Display | Yes | Yes |
| has a touch screen | Yes | Yes |
| waterproof depth rating | 50 m | 50 m |
| Watch band is replaceable | Yes | Yes |
| Has sapphire glass display | No | No |
| maximum operating temperature | 35 °C | — |
| Ingress Protection (IP) rating | IP68 | IP68 |
| has branded damage-resistant glass | Yes | No |
| lowest potential operating temperature | 0 °C | — |
| is designed for kids | — | No |
| Battery | ||
| battery life | 0.75 days | 0.75 days |
| has wireless charging | Yes | Yes |
| has a removable battery | No | No |
| Has a solar power battery | No | No |
| has a rechargeable battery | Yes | Yes |
| battery life in power save mode | 32 hours | 36 hours |
| charge time | — | 1.2 hours |
| Sensors | ||
| has GPS | Yes | Yes |
| has a compass | Yes | Yes |
| Has a barometer | Yes | Yes |
| has a gyroscope | Yes | Yes |
| Has a cadence sensor | No | No |
| has an accelerometer | Yes | Yes |
| Monitors perspiration | No | No |
| Has a heart rate monitor | Yes | Yes |
| Has a temperature sensor | Yes | Yes |
| Monitors blood oxygenation levels | No | Yes |
| Features | ||
| release date | 2025-09-09 | 2023-09-12 |
| Has a stopwatch | Yes | Yes |
| Has smart alarm | Yes | No |
| Has call control | Yes | Yes |
| Has silent alarm | Yes | Yes |
| internal storage | 64GB | 64GB |
| measures VO2 max | No | Yes |
| Has notifications | Yes | Yes |
| Locates your phone | Yes | Yes |
| has a front camera | No | No |
| has fall detection | Yes | Yes |
| has voice commands | Yes | Yes |
| Acquires GPS faster | No | No |
| Has vibrating alerts | Yes | Yes |
| number of microphones | 1 | 1 |
| shows readiness level | No | No |
| Can be used to answer calls | Yes | Yes |
| measures resting heart rate | Yes | Yes |
| has irregular heart rate warnings | Yes | Yes |
| has fast/slow heart rate notifications | Yes | Yes |
| Has a built-in camera remote control function | Yes | Yes |
| RAM | — | 1GB |
| warranty period | — | 1 years |
| has HRV tracking | — | Yes |
| Has ECG technology | — | Yes |
| Connectivity | ||
| has NFC | Yes | Yes |
| Wi-Fi version | Wi-Fi 4 (802.11n) | Wi-Fi 4 (802.11n) |
| supports ANT+ | No | No |
| supports Wi-Fi | Yes | Yes |
| supports Galileo | Yes | Yes |
| Bluetooth version | 5.3 | 5.3 |
| has a cellular module | No | No |
| Is compatible with iOS | Yes | Yes |
| Is compatible with Android | No | No |
| Miscellaneous | ||
| has aptX | No | No |
| Has passcode | Yes | Yes |
| Has auto pause | Yes | Yes |
| has crash detection | Yes | Yes |
| Is compatible with Windows | No | No |
| Is compatible with Mac OS X | Yes | No |
| has an external memory slot | No | No |
| Compatible with smart scales | Yes | Yes |
| has a battery level indicator | Yes | Yes |
| has a socket for a 3.5 mm audio jack | No | No |
| Compatible with external heart rate monitors | Yes | Yes |
| App & Software | ||
| Ad-free | Yes | Yes |
| Free app | Yes | Yes |
| Has coaching | No | No |
| Has achievements | Yes | Yes |
| Has goal setting | Yes | Yes |
| Has exercise diary | Yes | Yes |
| Predicts ovulation | Yes | Yes |
| Can be personalised | Yes | Yes |
| Has weight tracking | No | Yes |
| Predicts start date | Yes | Yes |
| Tracks water intake | No | Yes |
| Has inactivity alerts | Yes | Yes |
| Has period notifications | Yes | Yes |
| Has temperature tracking | Yes | Yes |
| Provides activity reports | Yes | Yes |
| Counts how many calories you've burned | Yes | Yes |
| Activity tracking | ||
| Measures pace | Yes | Yes |
| Tracks distance | Yes | Yes |
| Tracks elevation | Yes | Yes |
| Designed for golf | No | No |
| Tracks your sleep | Yes | Yes |
| Tracks steps taken | Yes | Yes |
| Designed for diving | No | No |
| Has a route tracker | Yes | Yes |
| Has exercise tagging | Yes | Yes |
| Has multi-sport mode | Yes | Yes |
| Tracks calorie intake | No | Yes |
| Provides sleep reports | Yes | Yes |
| Detects activities automatically | Yes | Yes |
| Has a stroke counter for swimming | Yes | Yes |
Wrist Fit
Apple Watch SE 3 - GPS · 40mm
Sits best on wrists ~42–57mm wide (≈ 11.2–15.2cm circumference).
Apple Watch Series 9 - GPS · Aluminium · 41mm
Sits best on wrists ~43–59mm wide (≈ 11.5–15.8cm circumference).
Frequently Asked Questions
Is the Apple Watch SE 3 - GPS · 40mm bigger than the Apple Watch Series 9 - GPS · Aluminium · 41mm?
The Apple Watch Series 9 - GPS · Aluminium · 41mm is bigger — 35mm vs 34mm case width.
Which fits a smaller wrist better, the Apple Watch SE 3 - GPS · 40mm or the Apple Watch Series 9 - GPS · Aluminium · 41mm?
The Apple Watch SE 3 - GPS · 40mm suits wrists around 42–57mm wide, and the Apple Watch Series 9 - GPS · Aluminium · 41mm around 43–59mm. The one with the smaller lower bound is the safer pick for a small wrist.
Can I see the Apple Watch SE 3 - GPS · 40mm and Apple Watch Series 9 - GPS · Aluminium · 41mm side by side at true scale?
Yes — the schematics and photos above show both watches at matched scale, and our fit tool overlays each on your wrist width.