Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Amazfit - T-Rex 3 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| Battery life | 672 h | 36 h |
| Weight | 68 g | 37 g |
| Display size | 1.5 " | 1.4 " |
| Water resistance | 10 ATM | 5 ATM |
| ECG | false | true |
| Cellular | false | true |
Between the T-Rex 3 and Pixel Watch 3 (45mm), the T-Rex 3 comes out ahead in battery life / display size, while the Pixel Watch 3 (45mm) wins on weight / ecg. Overall, the T-Rex 3 scores 62.7 and the Pixel Watch 3 (45mm) scores 69.5 on our Mars Score.
Which should you buy?
The Pixel Watch 3 (45mm) edges ahead on the Mars Score (62.7 vs 69.5), but the 6.8-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the T-Rex 3 if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. The biggest gaps in its favor are battery life, display size, water resistance. The single most decisive one: Battery life — 1766.67% more. 672 h vs 36 h.
Pick the Pixel Watch 3 (45mm) if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are weight, ecg, cellular. The single most decisive one: Weight — 31.00 g less. 37 vs 68.
Both ship with comparable spo2, peak brightness, 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: Amazfit - T-Rex 3 or Google - Pixel Watch 3 (45mm)?
Google - Pixel Watch 3 (45mm) leads the current Mars Score by 6.8 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 Amazfit - T-Rex 3 if…
Amazfit - T-Rex 3 has the measurable edge on battery life h, display size in, water resistance atm.
Choose Google - Pixel Watch 3 (45mm) if…
Google - Pixel Watch 3 (45mm) has the measurable edge on weight g, has ecg, has cellular.
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 Amazfit - T-Rex 3 wins
- ▲Battery life — 1766.67% more. 672 h vs 36 h.
- ▲Display size — 7.14% more. 1.5 " vs 1.4 ".
- ▲Water resistance — 5.00 ATM more. 10 vs 5.
Why Google - Pixel Watch 3 (45mm) wins
- ▲Weight — 31.00 g less. 37 vs 68.
- ▲Has ECG.
- ▲Has Cellular.
Spec comparison
Design
| Spec | Amazfit - T-Rex 3 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| Case size | 48.5 mmlead | 45 mm |
| Weight | 68 g | 37 glead |
| Case material | polymer | aluminum |
| Water resistanceⓘ | 10 ATMlead | 5 ATM |
Display
| Spec | Amazfit - T-Rex 3 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| Display size | 1.5 "lead | 1.4 " |
| Always-on display | true | true |
| Peak brightnessⓘ | 2000 nits | 2000 nits |
Health & Fitness
| Spec | Amazfit - T-Rex 3 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| ECG | false | truelead |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Amazfit - T-Rex 3 | Google - Pixel Watch 3 (45mm) |
|---|---|---|
| Battery lifeⓘ | 672 hlead | 36 h |
| GPS | true | true |
| Cellular | false | truelead |
| NFC | false | truelead |
| OS | Zepp OSlead | WearOS |
Frequently asked
Which has longer battery life, T-Rex 3 or Pixel Watch 3 (45mm)?+
T-Rex 3 lasts 672 hours vs 36 hours.
Do T-Rex 3 or Pixel Watch 3 (45mm) support ECG?+
Pixel Watch 3 (45mm) supports ECG; T-Rex 3 does not.
Which has cellular, T-Rex 3 or Pixel Watch 3 (45mm)?+
Pixel Watch 3 (45mm) offers a cellular variant; T-Rex 3 is Wi-Fi only.