Apple Watch Ultra 3 vs Xiaomi Watch S4 Sport
Size, specs & wrist fit compared
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Which one fits you
On wrists narrower than about 52mm, the Xiaomi Watch S4 Sport is the safer pick — it stays proportionate down to roughly 49mm, where the Apple Watch Ultra 3 starts to hang over the edge. Above 52mm both sit cleanly, and the Apple Watch Ultra 3 gives you more presence.
The Xiaomi Watch S4 Sport wears larger than the Apple Watch Ultra 3 (46.9mm vs 44mm case), giving it more wrist presence — and needing a wider wrist to sit cleanly.
The Apple Watch Ultra 3 is the slimmer of the two (12mm vs 12.6mm), so it slides under a cuff more easily.
On the wrist the Xiaomi Watch S4 Sport feels lighter (49g vs 61.8g, case only).
Among the 326 44mm watches we hold thickness for, the Apple Watch Ultra 3 is thinner than 89%, so it wears flatter than its width suggests.
The Xiaomi Watch S4 Sport is middle-of-the-pack for thickness among the 97 47mm watches in the database.
The Xiaomi Watch S4 Sport is 2.9mm wider, 2.1mm shorter, 0.6mm thicker and 12.8g lighter than the Apple Watch Ultra 3.
Apple
Watch Ultra 3
Xiaomi
Watch S4 Sport
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Apple
Watch Ultra 3
Xiaomi
Watch S4 Sport
2D Dimension Schematics
Every case drawn to scale on a shared centre — from above, and in profile against the wrist.
- Apple Watch Ultra 344mm × 49mm · 12mm thick
- Xiaomi Watch S4 Sport46.9mm · 12.6mm thick
3D preview
Apple Watch Ultra 3 vs Xiaomi Watch S4 Sport 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
Furthest apart in Smartwatch mode, where the Xiaomi Watch S4 Sport lasts 8.6× as long as the Apple Watch Ultra 3 (15 days against 42 hours).
Apple Watch Ultra 3Xiaomi Watch S4 Sport
Smartwatch
1.75 days15 daysBattery Saver
72 hours—
Specifications
The short version
11 key specs| Spec | AppleWatch Ultra 3 | XiaomiWatch S4 Sport |
|---|---|---|
| Case Width | 44mm | 46.9mm |
| Lug-to-Lug | 49mm | 46.9mm |
| Thickness | 12mm | 12.6mm |
| Weight | 61.8g | 49g |
| Shape | Rectangle | Circular |
| Water Resistance | 10 ATM | 5 ATM |
| GPS | Yes | Yes |
| Display type | OLED/AMOLED | OLED/AMOLED |
| Screen size | 1.98 inches | 1.43 inches |
| Battery life | 1.75 days | 15 days |
| Released | 2025 | 2024 |
Every specification
121 specs| Spec | Apple Watch Ultra 3 | Xiaomi Watch S4 Sport |
|---|---|---|
| Design | ||
| width | 44 | 46.9 |
| height | 49 | 46.9 |
| volume | 25.87 cm³ | 27.72 cm³ |
| weight | 61.8 g | 49 g |
| thickness | 12 | 12.6 |
| ATM rating | 10 ATM | 5 ATM |
| resolution | 422 x 514 px | 466 x 466 px |
| screen size | 1.98 inches | 1.43 inches |
| Display type | OLED/AMOLED | OLED/AMOLED |
| Has a display | Yes | Yes |
| pixel density | 326 ppi | 326 ppi |
| water resistance | Waterproof | Waterproof |
| Always-On Display | Yes | Yes |
| has a touch screen | Yes | Yes |
| is designed for kids | No | No |
| waterproof depth rating | 100 m | 40 m |
| Watch band is replaceable | Yes | Yes |
| Has sapphire glass display | Yes | Yes |
| maximum operating temperature | 55 °C | — |
| Ingress Protection (IP) rating | IPX6 | — |
| has branded damage-resistant glass | No | No |
| lowest potential operating temperature | -20 °C | — |
| width of band | — | 22 mm |
| Battery | ||
| charge time | 1.5 hours | — |
| battery life | 1.75 days | 15 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 | 72 hours | — |
| battery power | — | 586 mAh |
| 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 | Yes | Yes |
| Features | ||
| RAM | 2GB | — |
| release date | 2025-09-09 | 2024-07-19 |
| Has a stopwatch | Yes | Yes |
| Has smart alarm | No | No |
| warranty period | 1 years | 1 years |
| Has call control | Yes | Yes |
| Has silent alarm | Yes | Yes |
| has HRV tracking | Yes | Yes |
| internal storage | 64GB | 32GB |
| measures VO2 max | Yes | Yes |
| Has notifications | Yes | Yes |
| Has ECG technology | Yes | No |
| Locates your phone | Yes | Yes |
| has a front camera | No | No |
| has fall detection | Yes | No |
| has voice commands | Yes | Yes |
| Acquires GPS faster | Yes | Yes |
| Has vibrating alerts | Yes | Yes |
| number of microphones | 1 | 1 |
| Can be used to answer calls | Yes | Yes |
| measures resting heart rate | Yes | Yes |
| has irregular heart rate warnings | Yes | No |
| has fast/slow heart rate notifications | Yes | Yes |
| Has a built-in camera remote control function | Yes | Yes |
| shows readiness level | — | Yes |
| Connectivity | ||
| has NFC | Yes | Yes |
| SIM cards | 1 eSIM | 1 eSIM |
| Wi-Fi version | Wi-Fi 4 (802.11n) | — |
| supports ANT+ | No | No |
| supports Wi-Fi | Yes | No |
| supports Galileo | Yes | Yes |
| Bluetooth version | 5.3 | 5.2 |
| has a cellular module | Yes | Yes |
| Is compatible with iOS | Yes | Yes |
| Is compatible with Android | No | Yes |
| Miscellaneous | ||
| has aptX | No | — |
| Has passcode | Yes | Yes |
| Has auto pause | Yes | — |
| has crash detection | Yes | — |
| Is compatible with Windows | No | No |
| Is compatible with Mac OS X | No | No |
| has an external memory slot | No | No |
| Compatible with smart scales | 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 | — |
| App & Software | ||
| Ad-free | Yes | Yes |
| Free app | Yes | Yes |
| Has coaching | No | No |
| Includes maps | Yes | Yes |
| Supports routes | Yes | 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 | Yes | Yes |
| Predicts start date | Yes | Yes |
| Tracks water intake | Yes | Yes |
| Has inactivity alerts | Yes | Yes |
| Has period notifications | Yes | Yes |
| Has temperature tracking | Yes | Yes |
| Provides activity reports | Yes | Yes |
| Displays fertile window notifications | Yes | — |
| Counts how many calories you've burned | Yes | Yes |
| Doesn’t require account | — | No |
| Activity tracking | ||
| Measures pace | Yes | Yes |
| Tracks distance | Yes | Yes |
| Tracks elevation | Yes | Yes |
| Designed for golf | No | — |
| Tracks your sleep | Yes | Yes |
| Tracks steps taken | Yes | Yes |
| Designed for diving | Yes | Yes |
| Has a route tracker | Yes | Yes |
| Has exercise tagging | Yes | Yes |
| Has multi-sport mode | 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 Ultra 3
Sits best on wrists ~52–70mm wide (≈ 13.9–18.7cm circumference).
Xiaomi Watch S4 Sport
Sits best on wrists ~49–67mm wide (≈ 13.1–17.9cm circumference).
Frequently Asked Questions
Is the Apple Watch Ultra 3 bigger than the Xiaomi Watch S4 Sport?
The Xiaomi Watch S4 Sport is bigger — 46.9mm vs 44mm case width.
Which fits a smaller wrist better, the Apple Watch Ultra 3 or the Xiaomi Watch S4 Sport?
The Apple Watch Ultra 3 suits wrists around 52–70mm wide, and the Xiaomi Watch S4 Sport around 49–67mm. The one with the smaller lower bound is the safer pick for a small wrist.
Can I see the Apple Watch Ultra 3 and Xiaomi Watch S4 Sport 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.