Between the Watch Ultra 3 and ScanWatch 2, the Watch Ultra 3 comes out ahead in display size and water resistance, while the ScanWatch 2 wins on battery life and weight. Overall, the Watch Ultra 3 scores 65.3 and the ScanWatch 2 scores 72.6 on our Mars Score.
Which should you buy?
The ScanWatch 2 edges ahead on the Mars Score (65.3 vs 72.6), but the 7.3-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the Watch Ultra 3 if you care most about display size and water resistance. The biggest gaps in its favor are display size, water resistance, cellular, among others.
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, 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 Apple - Watch Ultra 3 wins
- ▲Display size — 223.81% more. 2.04 " vs 0.63 ".
- ▲Water resistance — 5.00 ATM more. 10 vs 5.
- ▲Has Cellular.
- ▲Peak brightness: 3000 nits vs 0 nits.
Why Withings - ScanWatch 2 wins
- ▲Battery life — 900.00% more. 720 h vs 72 h.
- ▲Weight — 3.00 g less. 59 vs 62.
Spec comparison
Design
| Spec | Apple - Watch Ultra 3 | Withings - ScanWatch 2 |
|---|---|---|
| Case size | 49 mmlead | 42 mm |
| Weight | 62 g | 59 glead |
| Case material | titanium | stainless steel |
| Water resistanceⓘ | 10 ATMlead | 5 ATM |
Display
| Spec | Apple - Watch Ultra 3 | Withings - ScanWatch 2 |
|---|---|---|
| Display size | 2.04 "lead | 0.63 " |
| Always-on display | truelead | false |
| Peak brightnessⓘ | 3000 nitslead | 0 nits |
Health & Fitness
| Spec | Apple - Watch Ultra 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 | Apple - Watch Ultra 3 | Withings - ScanWatch 2 |
|---|---|---|
| Battery life | 72 h | 720 hlead |
| GPS | truelead | false |
| Cellular | truelead | false |
| NFC | truelead | false |
| OS | watchOS | Withings OSlead |
Frequently asked
Which has longer battery life, Watch Ultra 3 or ScanWatch 2?+
ScanWatch 2 lasts 720h vs 72h.
Do Watch Ultra 3 or ScanWatch 2 support ECG?+
Both support ECG.
Which has cellular, Watch Ultra 3 or ScanWatch 2?+
Watch Ultra 3 offers a cellular variant; ScanWatch 2 is Wi-Fi only.
Spec-level deep dives
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