Between the Pixel Watch 3 (45mm) and Watch S4, the Pixel Watch 3 (45mm) comes out ahead in weight, while the Watch S4 wins on battery life and peak brightness. Overall, the Pixel Watch 3 (45mm) scores 46.7 and the Watch S4 scores 63.9 on our Mars Score.
Which should you buy?
The Watch S4 is the clear pick on raw spec strength, leading by 17.2 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
Pick the Pixel Watch 3 (45mm) if you carry the device everywhere and weight or thickness has been the deciding factor before. The biggest gaps in its favor are 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, display size.
Both ship with comparable ecg, cellular, spo2, 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 Google - Pixel Watch 3 (45mm) wins
- ▲Weight — 7.00 g less. 37 vs 44.
Why Xiaomi - Watch S4 wins
- ▲Battery life — 900.00% more. 360 h vs 36 h.
- ▲Peak brightness — 10.00% more. 2200 nits vs 2000 nits.
- ▲Display size — 2.14% more. 1.43 " vs 1.4 ".
Spec comparison
Design
| Spec | Google - Pixel Watch 3 (45mm) | Xiaomi - Watch S4 |
|---|---|---|
| Case size | 45 mm | 47 mmlead |
| Weight | 37 glead | 44 g |
| Case material | aluminum | stainless steel |
| Water resistanceⓘ | 5 ATM | 5 ATM |
Display
| Spec | Google - Pixel Watch 3 (45mm) | Xiaomi - Watch S4 |
|---|---|---|
| Display size | 1.4 " | 1.43 "lead |
| Always-on display | true | true |
| Peak brightnessⓘ | 2000 nits | 2200 nitslead |
Health & Fitness
| Spec | Google - Pixel Watch 3 (45mm) | Xiaomi - Watch S4 |
|---|---|---|
| ECG | true | true |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Google - Pixel Watch 3 (45mm) | Xiaomi - Watch S4 |
|---|---|---|
| Battery life | 36 h | 360 hlead |
| GPS | true | true |
| Cellular | true | true |
| NFC | true | true |
| OS | WearOS | HyperOSlead |
Frequently asked
Which has longer battery life, Pixel Watch 3 (45mm) or Watch S4?+
Watch S4 lasts 360h vs 36h.
Do Pixel Watch 3 (45mm) or Watch S4 support ECG?+
Both support ECG.
Which has cellular, Pixel Watch 3 (45mm) or Watch S4?+
Both offer cellular variants.
Spec-level deep dives
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