Surface Gravity Calculator

How to Use This Calculator

1. Enter planet mass in kg and radius in meters to compute surface gravity.
2. Or use From Density & Radius tab if you know mean density.
3. Select a preset in the Solar System tab for instant comparisons.
4. Professional tier adds your weight on that world, latitude correction, and altitude variation.

Formula

Example

Frequently Asked Questions

• What is surface gravity? ▼
  Surface gravity is the gravitational acceleration at a body's surface: g = GM/r², where G = 6.67430×10⁻¹¹ N·m²/kg², M is the body's mass, and r is its radius. Earth's surface gravity is ~9.807 m/s².
• How much would I weigh on Mars? ▼
  Mars has a surface gravity of ~3.72 m/s² (0.379 g). A 70 kg person weighs 70 × 9.81 = 686 N on Earth but only 70 × 3.72 = 260 N on Mars.
• Why is Jupiter's surface gravity only ~2.5g despite its huge mass? ▼
  Jupiter is enormous — its radius is 11× Earth's. Since g = GM/r², the huge radius partially offsets the large mass. Jupiter's surface gravity is ~24.8 m/s² = 2.53g.
• Can I calculate g from density and radius? ▼
  Yes: g = (4/3)πGρr, where ρ is the average density and r is the radius. This is useful when density is known but exact mass is not.
• How does gravity vary with latitude on Earth? ▼
  Earth is slightly oblate (flattened at poles). Equatorial g ≈ 9.780 m/s², polar g ≈ 9.832 m/s². The difference is due to both shape and centrifugal effect from rotation.

Related Calculators