Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch Ultra 2 |
|---|---|---|
| Battery life | 672 h | 60 h |
| Peak brightness | 2000 nits | 3000 nits |
| Weight | 68 g | 60 g |
| ECG | false | true |
| Cellular | false | true |
Between the T-Rex 3 and Galaxy Watch Ultra 2, the T-Rex 3 comes out ahead in battery life, while the Galaxy Watch Ultra 2 wins on peak brightness / weight. Overall, the T-Rex 3 scores 62.7 and the Galaxy Watch Ultra 2 scores 67.5 on our Mars Score.
Which should you buy?
The Galaxy Watch Ultra 2 edges ahead on the Mars Score (62.7 vs 67.5), but the 4.8-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. The single most decisive one: Battery life — 1020.00% more. 672 h vs 60 h.
Pick the Galaxy Watch Ultra 2 if the display is what you stare at all day — refresh rate, brightness, or sharpness is where the difference will be most visible. Its strongest claims are peak brightness, weight, ecg, among others. The single most decisive one: Peak brightness — 50.00% more. 3000 nits vs 2000 nits.
Both ship with comparable display size, spo2, water resistance, so those specs do not separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.
Which should you buy: Amazfit - T-Rex 3 or Samsung - Galaxy Watch Ultra 2?
Samsung - Galaxy Watch Ultra 2 leads the current Mars Score by 4.8 points.The more useful decision is the trade-off behind that result: compare 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.
Choose Samsung - Galaxy Watch Ultra 2 if…
Samsung - Galaxy Watch Ultra 2 has the measurable edge on peak brightness nits, weight g, 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 Amazfit - T-Rex 3 wins
- ▲Battery life — 1020.00% more. 672 h vs 60 h.
Why Samsung - Galaxy Watch Ultra 2 wins
- ▲Peak brightness — 50.00% more. 3000 nits vs 2000 nits.
- ▲Weight — 8.00 g less. 60 vs 68.
- ▲Has ECG.
- ▲Has Cellular.
Spec comparison
Design
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch Ultra 2 |
|---|---|---|
| Case size | 48.5 mmlead | 47 mm |
| Weight | 68 g | 60 glead |
| Case material | polymer | titanium |
| Water resistanceⓘ | 10 ATM | 10 ATM |
Display
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch Ultra 2 |
|---|---|---|
| Display size | 1.5 " | 1.5 " |
| Always-on display | true | true |
| Peak brightnessⓘ | 2000 nits | 3000 nitslead |
Health & Fitness
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch Ultra 2 |
|---|---|---|
| ECG | false | truelead |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | false | truelead |
Battery & Connectivity
| Spec | Amazfit - T-Rex 3 | Samsung - Galaxy Watch Ultra 2 |
|---|---|---|
| Battery lifeⓘ | 672 hlead | 60 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 Galaxy Watch Ultra 2?+
T-Rex 3 lasts 672 hours vs 60 hours.
Do T-Rex 3 or Galaxy Watch Ultra 2 support ECG?+
Galaxy Watch Ultra 2 supports ECG; T-Rex 3 does not.
Which has cellular, T-Rex 3 or Galaxy Watch Ultra 2?+
Galaxy Watch Ultra 2 offers a cellular variant; T-Rex 3 is Wi-Fi only.