Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Samsung - Galaxy Watch 7 (44mm) | OnePlus Watch 3 |
|---|---|---|
| Battery life | 40 h | 120 h |
| Weight | 34 g | 81 g |
| Peak brightness | 3000 nits | 2200 nits |
| Display size | 1.47 " | 1.5 " |
| Cellular | true | false |
Between the Galaxy Watch 7 (44mm) and OnePlus Watch 3, the Galaxy Watch 7 (44mm) comes out ahead in weight / peak brightness, while the OnePlus Watch 3 wins on battery life / display size. Overall, the Galaxy Watch 7 (44mm) scores 70.9 and the OnePlus Watch 3 scores 65.7 on our Mars Score.
Which should you buy?
The Galaxy Watch 7 (44mm) edges ahead on the Mars Score (70.9 vs 65.7), but the 5.2-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the Galaxy Watch 7 (44mm) if the display is what you stare at all day — refresh rate, brightness, or sharpness is where the difference will be most visible. The biggest gaps in its favor are weight, peak brightness, cellular. The single most decisive one: Weight — 47.00 g less. 34 vs 81.
Pick the OnePlus Watch 3 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, display size. The single most decisive one: Battery life — 200.00% more. 120 h vs 40 h.
Both ship with comparable ecg, spo2, water resistance, so those specs do not separate the two — focus on the differences below.
Bottom line: the Galaxy Watch 7 (44mm) 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: Samsung - Galaxy Watch 7 (44mm) or OnePlus Watch 3?
Samsung - Galaxy Watch 7 (44mm) leads the current Mars Score by 5.2 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 Samsung - Galaxy Watch 7 (44mm) if…
Samsung - Galaxy Watch 7 (44mm) has the measurable edge on weight g, peak brightness nits, has cellular.
Choose OnePlus Watch 3 if…
OnePlus Watch 3 has the measurable edge on battery life h, display size in.
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 Samsung - Galaxy Watch 7 (44mm) wins
- ▲Weight — 47.00 g less. 34 vs 81.
- ▲Peak brightness — 36.36% more. 3000 nits vs 2200 nits.
- ▲Has Cellular.
Why OnePlus Watch 3 wins
- ▲Battery life — 200.00% more. 120 h vs 40 h.
- ▲Display size — 2.04% more. 1.5 " vs 1.47 ".
Spec comparison
Design
| Spec | Samsung - Galaxy Watch 7 (44mm) | OnePlus Watch 3 |
|---|---|---|
| Case size | 44 mm | 46.5 mmlead |
| Weight | 34 glead | 81 g |
| Case material | aluminum | stainless steel |
| Water resistanceⓘ | 5 ATM | 5 ATM |
Display
| Spec | Samsung - Galaxy Watch 7 (44mm) | OnePlus Watch 3 |
|---|---|---|
| Display size | 1.47 " | 1.5 "lead |
| Always-on display | true | true |
| Peak brightnessⓘ | 3000 nitslead | 2200 nits |
Health & Fitness
| Spec | Samsung - Galaxy Watch 7 (44mm) | OnePlus Watch 3 |
|---|---|---|
| ECG | true | true |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | truelead | false |
Battery & Connectivity
| Spec | Samsung - Galaxy Watch 7 (44mm) | OnePlus Watch 3 |
|---|---|---|
| Battery lifeⓘ | 40 h | 120 hlead |
| GPS | true | true |
| Cellular | truelead | false |
| NFC | true | true |
| OS | WearOS | WearOS |
Frequently asked
Which has longer battery life, Galaxy Watch 7 (44mm) or OnePlus Watch 3?+
OnePlus Watch 3 lasts 120 hours vs 40 hours.
Do Galaxy Watch 7 (44mm) or OnePlus Watch 3 support ECG?+
Both support ECG.
Which has cellular, Galaxy Watch 7 (44mm) or OnePlus Watch 3?+
Galaxy Watch 7 (44mm) offers a cellular variant; OnePlus Watch 3 is Wi-Fi only.