Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Samsung - Galaxy Watch 6 Classic | OnePlus Watch 3 |
|---|---|---|
| Battery life | 40 h | 120 h |
| Weight | 59 g | 81 g |
| Peak brightness | 2000 nits | 2200 nits |
| Display size | 1.47 " | 1.5 " |
| Cellular | true | false |
Between the Galaxy Watch 6 Classic and OnePlus Watch 3, the Galaxy Watch 6 Classic comes out ahead in weight / cellular, while the OnePlus Watch 3 wins on battery life / peak brightness. Overall, the Galaxy Watch 6 Classic scores 66.8 and the OnePlus Watch 3 scores 65.7 on our Mars Score.
Which should you buy?
These two are nearly even on the Mars Score (66.8 vs 65.7). The decision is not about overall quality — both clear the bar — it is about which specific trade-offs fit your use.
Pick the Galaxy Watch 6 Classic if you carry the device everywhere and weight or thickness has been the deciding factor before. The biggest gaps in its favor are weight, cellular. The single most decisive one: Weight — 22.00 g less. 59 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, peak brightness, 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: 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: Samsung - Galaxy Watch 6 Classic or OnePlus Watch 3?
Samsung - Galaxy Watch 6 Classic leads the current Mars Score by 1.1 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 6 Classic if…
Samsung - Galaxy Watch 6 Classic has the measurable edge on weight g, has cellular.
Choose OnePlus Watch 3 if…
OnePlus Watch 3 has the measurable edge on battery life h, peak brightness nits, 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 6 Classic wins
- ▲Weight — 22.00 g less. 59 vs 81.
- ▲Has Cellular.
Why OnePlus Watch 3 wins
- ▲Battery life — 200.00% more. 120 h vs 40 h.
- ▲Peak brightness — 10.00% more. 2200 nits vs 2000 nits.
- ▲Display size — 2.04% more. 1.5 " vs 1.47 ".
Spec comparison
Design
| Spec | Samsung - Galaxy Watch 6 Classic | OnePlus Watch 3 |
|---|---|---|
| Case size | 47 mmlead | 46.5 mm |
| Weight | 59 glead | 81 g |
| Case material | stainless steel | stainless steel |
| Water resistanceⓘ | 5 ATM | 5 ATM |
Display
| Spec | Samsung - Galaxy Watch 6 Classic | OnePlus Watch 3 |
|---|---|---|
| Display size | 1.47 " | 1.5 "lead |
| Always-on display | true | true |
| Peak brightnessⓘ | 2000 nits | 2200 nitslead |
Health & Fitness
| Spec | Samsung - Galaxy Watch 6 Classic | 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 6 Classic | 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 6 Classic or OnePlus Watch 3?+
OnePlus Watch 3 lasts 120 hours vs 40 hours.
Do Galaxy Watch 6 Classic or OnePlus Watch 3 support ECG?+
Both support ECG.
Which has cellular, Galaxy Watch 6 Classic or OnePlus Watch 3?+
Galaxy Watch 6 Classic offers a cellular variant; OnePlus Watch 3 is Wi-Fi only.