Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Garmin - Fenix 8 (47mm) | Polar - Vantage V3 |
|---|---|---|
| Battery life | 384 h | 168 h |
| Weight | 73 g | 57 g |
| Water resistance | 10 ATM | 5 ATM |
| Display size | 1.4 " | 1.39 " |
Between the Fenix 8 (47mm) and Vantage V3, the Fenix 8 (47mm) comes out ahead in battery life / water resistance, while the Vantage V3 wins on weight. Overall, the Fenix 8 (47mm) scores 71.9 and the Vantage V3 scores 69.2 on our Mars Score.
Which should you buy?
These two are nearly even on the Mars Score (71.9 vs 69.2). The decision is not about overall quality — both clear the bar — it is about which specific trade-offs fit your use.
Pick the Fenix 8 (47mm) 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, water resistance, display size. The single most decisive one: Battery life — 128.57% more. 384 h vs 168 h.
Pick the Vantage V3 if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are weight. The single most decisive one: Weight — 16.00 g less. 57 vs 73.
Both ship with comparable ecg, cellular, spo2, 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: Garmin - Fenix 8 (47mm) or Polar - Vantage V3?
Garmin - Fenix 8 (47mm) leads the current Mars Score by 2.7 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 Garmin - Fenix 8 (47mm) if…
Garmin - Fenix 8 (47mm) has the measurable edge on battery life h, water resistance atm, display size in.
Choose Polar - Vantage V3 if…
Polar - Vantage V3 has the measurable edge on weight g.
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 Garmin - Fenix 8 (47mm) wins
- ▲Battery life — 128.57% more. 384 h vs 168 h.
- ▲Water resistance — 5.00 ATM more. 10 vs 5.
- ▲Display size — 0.72% more. 1.4 " vs 1.39 ".
Why Polar - Vantage V3 wins
- ▲Weight — 16.00 g less. 57 vs 73.
Spec comparison
Design
| Spec | Garmin - Fenix 8 (47mm) | Polar - Vantage V3 |
|---|---|---|
| Case size | 47 mm | 47 mm |
| Weight | 73 g | 57 glead |
| Case material | fiber-reinforced polymer | aluminum |
| Water resistanceⓘ | 10 ATMlead | 5 ATM |
Display
| Spec | Garmin - Fenix 8 (47mm) | Polar - Vantage V3 |
|---|---|---|
| Display size | 1.4 "lead | 1.39 " |
| Always-on display | true | true |
| Peak brightnessⓘ | 1000 nits | 1000 nits |
Health & Fitness
| Spec | Garmin - Fenix 8 (47mm) | Polar - Vantage V3 |
|---|---|---|
| ECG | true | true |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Garmin - Fenix 8 (47mm) | Polar - Vantage V3 |
|---|---|---|
| Battery lifeⓘ | 384 hlead | 168 h |
| GPS | true | true |
| Cellular | false | false |
| NFC | truelead | false |
| OS | Garmin OS | Polar OSlead |
Frequently asked
Which has longer battery life, Fenix 8 (47mm) or Vantage V3?+
Fenix 8 (47mm) lasts 384 hours vs 168 hours.
Do Fenix 8 (47mm) or Vantage V3 support ECG?+
Both support ECG.
Which has cellular, Fenix 8 (47mm) or Vantage V3?+
Neither offers cellular.