Between the OnePlus Watch 3 and ScanWatch 2, the OnePlus Watch 3 comes out ahead in display size and peak brightness, while the ScanWatch 2 wins on battery life and weight. Overall, the OnePlus Watch 3 scores 53.9 and the ScanWatch 2 scores 72.6 on our Mars Score.
Which should you buy?
The ScanWatch 2 is the clear pick on raw spec strength, leading by 18.7 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 OnePlus Watch 3 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 display size, peak brightness.
Pick the ScanWatch 2 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, weight.
Both ship with comparable ecg, cellular, spo2, so those specs don't separate the two — focus on the differences below.
Bottom line: the ScanWatch 2 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why OnePlus Watch 3 wins
- ▲Display size — 138.10% more. 1.5 " vs 0.63 ".
- ▲Peak brightness: 2200 nits vs 0 nits.
Why Withings - ScanWatch 2 wins
- ▲Battery life — 500.00% more. 720 h vs 120 h.
- ▲Weight — 22.00 g less. 59 vs 81.
Spec comparison
Design
| Spec | OnePlus Watch 3 | Withings - ScanWatch 2 |
|---|---|---|
| Case size | 46.5 mmlead | 42 mm |
| Weight | 81 g | 59 glead |
| Case material | stainless steel | stainless steel |
| Water resistanceⓘ | 5 ATM | 5 ATM |
Display
| Spec | OnePlus Watch 3 | Withings - ScanWatch 2 |
|---|---|---|
| Display size | 1.5 "lead | 0.63 " |
| Always-on display | truelead | false |
| Peak brightnessⓘ | 2200 nitslead | 0 nits |
Health & Fitness
| Spec | OnePlus Watch 3 | Withings - ScanWatch 2 |
|---|---|---|
| ECG | true | true |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | OnePlus Watch 3 | Withings - ScanWatch 2 |
|---|---|---|
| Battery life | 120 h | 720 hlead |
| GPS | truelead | false |
| Cellular | false | false |
| NFC | truelead | false |
| OS | WearOS | Withings OSlead |
Frequently asked
Which has longer battery life, OnePlus Watch 3 or ScanWatch 2?+
ScanWatch 2 lasts 720h vs 120h.
Do OnePlus Watch 3 or ScanWatch 2 support ECG?+
Both support ECG.
Which has cellular, OnePlus Watch 3 or ScanWatch 2?+
Neither offers cellular.
Spec-level deep dives
More from the same brands
vsMars is reader-supported. When you buy through links on our site, we may earn an affiliate commission at no extra cost to you. Learn more.