NewGarmin MARQ Adventurer (Gen 3) added to the catalogSee specs →Advertise
idk.devsmartwatches & bands, compared
  1. idk.dev
  2. Compare
  3. Fenix 9 47mm vs Fenix 9 51mm

Garmin Fenix 9 47mm vs Garmin Fenix 9 51mm

What Fenix 9 47mm does better (2) and where Fenix 9 51mm wins (4) — every spec side by side.

Garmin Fenix 9 47mm
Garmin · 2026Fenix 9 47mm
7.0Score
2 advantages≈ $1,000
vs
Garmin Fenix 9 51mm
Garmin · 2026Fenix 9 51mm
8.6Score
4 advantages≈ $1,100
Higher score
7.5Display7.5
5.2Battery life8.4
8.3Health tracking8.3
8.2Sports & outdoor8.2
3.2Smart features3.2
7.4Build & durability6.5
Dimensions

Size comparison

Fenix 9 47mmFenix 9 51mm
47 × 4713.851 × 5114.7
Fenix 9 47mmFenix 9 51mmDifference
Height47 mm51 mm−4 mm
Width47 mm51 mm−4 mm
Thickness13.8 mm14.7 mm−0.9 mm
Weight75 g91 g−16 g

Drawn to the same scale from the official dimensions (front and side).

Why is Fenix 9 47mm better than Fenix 9 51mm?

  1. Weight75 g vs 91 g+21%
  2. Thickness13.8 mm vs 14.7 mm+7%

Why is Fenix 9 51mm better than Fenix 9 47mm?

  1. Battery life (smartwatch mode)16 days vs 29 days+81%
  2. GPS battery life30 h vs 54 h+80%
  3. GPS battery life (dual-band)25 h vs 45 h+80%
  4. Battery saver mode24 days vs 42 days+75%
Specifications

Side by side

To compare: 0up to 4 models
Compare