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Apple - Watch Ultra 3 vs Garmin - Fenix 8 (47mm)

Last updated · How Mars Score works
Watch Ultra 3APPLERENDER
Probe A
Apple
Watch Ultra 3
65.3/ 100C
Health & Fitness· 32%
Battery & Connectivity42· 30%
Display92· 22%
Design· 16%
Fenix 8 (47mm)GARMINRENDER
Probe B
Garmin
Fenix 8 (47mm)
64.3/ 100C
Health & Fitness· 32%
Battery & Connectivity70· 30%
Display57· 22%
Design· 16%
Quick verdict

Between the Watch Ultra 3 and Fenix 8 (47mm), the Watch Ultra 3 comes out ahead in peak brightness and display size, while the Fenix 8 (47mm) wins on battery life. Overall, the Watch Ultra 3 scores 65.3 and the Fenix 8 (47mm) scores 64.3 on our Mars Score.

Buying advice

Which should you buy?

These two are nearly even on the Mars Score (65.3 vs 64.3). The decision isn't about overall quality — both clear the bar — it's about which specific trade-offs fit your use.

Pick the Watch Ultra 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 peak brightness, display size, weight, among others.

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. Its strongest claims are battery life.

Both ship with comparable ecg, spo2, water resistance, so those specs don't 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 tells you both are well-rounded; the differences are about trade-offs, not quality.

Why Apple - Watch Ultra 3 wins

  • Peak brightness — 200.00% more. 3000 nits vs 1000 nits.
  • Display size — 45.71% more. 2.04 " vs 1.4 ".
  • Weight — 11.00 g less. 62 vs 73.
  • Has Cellular.

Why Garmin - Fenix 8 (47mm) wins

  • Battery life — 433.33% more. 384 h vs 72 h.
Full readout

Spec comparison

Design

SpecApple - Watch Ultra 3Garmin - Fenix 8 (47mm)
Case size49 mmlead47 mm
Weight62 glead73 g
Case materialtitaniumfiber-reinforced polymer
Water resistance10 ATM10 ATM

Display

SpecApple - Watch Ultra 3Garmin - Fenix 8 (47mm)
Display size2.04 "lead1.4 "
Always-on displaytruetrue
Peak brightness3000 nitslead1000 nits

Health & Fitness

SpecApple - Watch Ultra 3Garmin - Fenix 8 (47mm)
ECGtruetrue
SpO2truetrue
Temperature sensortruetrue
Sleep trackingtruetrue
Blood pressurefalsefalse

Battery & Connectivity

SpecApple - Watch Ultra 3Garmin - Fenix 8 (47mm)
Battery life72 h384 hlead
GPStruetrue
Cellulartrueleadfalse
NFCtruetrue
OSwatchOSGarmin OSlead
Reader questions

Frequently asked

Which has longer battery life, Watch Ultra 3 or Fenix 8 (47mm)?+

Fenix 8 (47mm) lasts 384h vs 72h.

Do Watch Ultra 3 or Fenix 8 (47mm) support ECG?+

Both support ECG.

Which has cellular, Watch Ultra 3 or Fenix 8 (47mm)?+

Watch Ultra 3 offers a cellular variant; Fenix 8 (47mm) is Wi-Fi only.

Drill down

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