Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Apple - Watch SE 3 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| Battery life | 18 h | 36 h |
| Peak brightness | 1000 nits | 2000 nits |
| Display size | 1.78 " | 1.4 " |
| Weight | 33 g | 37 g |
| ECG | false | true |
| SpO2 | false | true |
Between the Watch SE 3 and Pixel Watch 3 (45mm), the Watch SE 3 comes out ahead in display size / weight, while the Pixel Watch 3 (45mm) wins on battery life / peak brightness. Overall, the Watch SE 3 scores 55.9 and the Pixel Watch 3 (45mm) scores 69.5 on our Mars Score.
Which should you buy?
The Pixel Watch 3 (45mm) is the clear pick on raw spec strength, leading by 13.6 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 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. The single most decisive one: Display size — 27.14% more. 1.78 " vs 1.4 ".
Pick the Pixel Watch 3 (45mm) 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. The single most decisive one: Battery life — 100.00% more. 36 h vs 18 h.
Both ship with comparable cellular, water resistance, so those specs do not separate the two — focus on the differences below.
Bottom line: the Pixel Watch 3 (45mm) is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Which should you buy: Apple - Watch SE 3 or Google - Pixel Watch 3 (45mm)?
Google - Pixel Watch 3 (45mm) leads the current Mars Score by 13.6 points.The more useful decision is the trade-off behind that result: compare display size, battery life against the way you will actually use the product.
Choose Apple - Watch SE 3 if…
Apple - Watch SE 3 has the measurable edge on display size in, weight g.
Choose Google - Pixel Watch 3 (45mm) if…
Google - Pixel Watch 3 (45mm) has the measurable edge on battery life h, peak brightness nits, has ecg.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Apple - Watch SE 3 wins
- ▲Display size — 27.14% more. 1.78 " vs 1.4 ".
- ▲Weight — 4.00 g less. 33 vs 37.
Why Google - Pixel Watch 3 (45mm) wins
- ▲Battery life — 100.00% more. 36 h vs 18 h.
- ▲Peak brightness — 100.00% more. 2000 nits vs 1000 nits.
- ▲Has ECG.
- ▲Has SpO2.
Spec comparison
Design
| Spec | Apple - Watch SE 3 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| Case size | 44 mm | 45 mmlead |
| Weight | 33 glead | 37 g |
| Case material | aluminum | aluminum |
| Water resistanceⓘ | 5 ATM | 5 ATM |
Display
| Spec | Apple - Watch SE 3 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| Display size | 1.78 "lead | 1.4 " |
| Always-on display | false | truelead |
| Peak brightnessⓘ | 1000 nits | 2000 nitslead |
Health & Fitness
| Spec | Apple - Watch SE 3 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| 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 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| Battery lifeⓘ | 18 h | 36 hlead |
| GPS | true | true |
| Cellular | true | true |
| NFC | true | true |
| OS | watchOS | WearOSlead |
Frequently asked
Which has longer battery life, Watch SE 3 or Pixel Watch 3 (45mm)?+
Pixel Watch 3 (45mm) lasts 36 hours vs 18 hours.
Do Watch SE 3 or Pixel Watch 3 (45mm) support ECG?+
Pixel Watch 3 (45mm) supports ECG; Watch SE 3 does not.
Which has cellular, Watch SE 3 or Pixel Watch 3 (45mm)?+
Both offer cellular variants.