Between the Fenix 8 (47mm) and vívoactive 5, the Fenix 8 (47mm) comes out ahead in battery life and display size, while the vívoactive 5 wins on weight. Overall, the Fenix 8 (47mm) scores 64.3 and the vívoactive 5 scores 53.3 on our Mars Score.
Which should you buy?
The Fenix 8 (47mm) is the clear pick on raw spec strength, leading by 11.0 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 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, display size, water resistance, among others.
Pick the vívoactive 5 if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are weight.
Both ship with comparable cellular, spo2, peak brightness, so those specs don't separate the two — focus on the differences below.
Bottom line: the Fenix 8 (47mm) is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Garmin - Fenix 8 (47mm) wins
- ▲Battery life — 45.45% more. 384 h vs 264 h.
- ▲Display size — 16.67% more. 1.4 " vs 1.2 ".
- ▲Water resistance — 5.00 ATM more. 10 vs 5.
- ▲Has ECG.
Why Garmin - vívoactive 5 wins
- ▲Weight — 47.00 g less. 26 vs 73.
Spec comparison
Design
| Spec | Garmin - Fenix 8 (47mm) | Garmin - vívoactive 5 |
|---|---|---|
| Case size | 47 mmlead | 42 mm |
| Weight | 73 g | 26 glead |
| Case material | fiber-reinforced polymer | polymer |
| Water resistanceⓘ | 10 ATMlead | 5 ATM |
Display
| Spec | Garmin - Fenix 8 (47mm) | Garmin - vívoactive 5 |
|---|---|---|
| Display size | 1.4 "lead | 1.2 " |
| Always-on display | true | true |
| Peak brightnessⓘ | 1000 nits | 1000 nits |
Health & Fitness
| Spec | Garmin - Fenix 8 (47mm) | Garmin - vívoactive 5 |
|---|---|---|
| ECG | truelead | false |
| SpO2 | true | true |
| Temperature sensor | truelead | false |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Garmin - Fenix 8 (47mm) | Garmin - vívoactive 5 |
|---|---|---|
| Battery life | 384 hlead | 264 h |
| GPS | true | true |
| Cellular | false | false |
| NFC | true | true |
| OS | Garmin OS | Garmin OS |
Frequently asked
Which has longer battery life, Fenix 8 (47mm) or vívoactive 5?+
Fenix 8 (47mm) lasts 384h vs 264h.
Do Fenix 8 (47mm) or vívoactive 5 support ECG?+
Fenix 8 (47mm) supports ECG; vívoactive 5 does not.
Which has cellular, Fenix 8 (47mm) or vívoactive 5?+
Neither offers cellular.
Spec-level deep dives
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