Between the Watch SE 3 and Watch S4, the Watch SE 3 comes out ahead in display size and weight, while the Watch S4 wins on battery life and peak brightness. Overall, the Watch SE 3 scores 56.1 and the Watch S4 scores 63.9 on our Mars Score.
Which should you buy?
The Watch S4 edges ahead on the Mars Score (56.1 vs 63.9), but the 7.8-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the Watch SE 3 if you carry the device everywhere and weight or thickness has been the deciding factor before. The biggest gaps in its favor are display size, weight.
Pick the Watch S4 if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. Its strongest claims are battery life, peak brightness, ecg, among others.
Both ship with comparable cellular, water resistance, so those specs don't separate the two — focus on the differences below.
Bottom line: the Watch S4 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Apple - Watch SE 3 wins
- ▲Display size — 24.48% more. 1.78 " vs 1.43 ".
- ▲Weight — 11.00 g less. 33 vs 44.
Why Xiaomi - Watch S4 wins
- ▲Battery life — 1900.00% more. 360 h vs 18 h.
- ▲Peak brightness — 120.00% more. 2200 nits vs 1000 nits.
- ▲Has ECG.
- ▲Has SpO2.
Spec comparison
Design
| Spec | Apple - Watch SE 3 | Xiaomi - Watch S4 |
|---|---|---|
| Case size | 44 mm | 47 mmlead |
| Weight | 33 glead | 44 g |
| Case material | aluminum | stainless steel |
| Water resistanceⓘ | 5 ATM | 5 ATM |
Display
| Spec | Apple - Watch SE 3 | Xiaomi - Watch S4 |
|---|---|---|
| Display size | 1.78 "lead | 1.43 " |
| Always-on display | false | truelead |
| Peak brightnessⓘ | 1000 nits | 2200 nitslead |
Health & Fitness
| Spec | Apple - Watch SE 3 | Xiaomi - Watch S4 |
|---|---|---|
| ECG | false | truelead |
| SpO2 | false | truelead |
| Temperature sensor | false | truelead |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Apple - Watch SE 3 | Xiaomi - Watch S4 |
|---|---|---|
| Battery life | 18 h | 360 hlead |
| GPS | true | true |
| Cellular | true | true |
| NFC | true | true |
| OS | watchOS | HyperOSlead |
Frequently asked
Which has longer battery life, Watch SE 3 or Watch S4?+
Watch S4 lasts 360h vs 18h.
Do Watch SE 3 or Watch S4 support ECG?+
Watch S4 supports ECG; Watch SE 3 does not.
Which has cellular, Watch SE 3 or Watch S4?+
Both offer cellular variants.
Spec-level deep dives
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