Physics

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Escape Velocity Calculator.

Calculate ideal two-body escape velocity from mass and radius.

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Escape velocity: 11,185.977892

Escape velocity

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Educational SI model using the assumptions stated above; verify engineering and safety decisions independently.

Use Cases

Space Mission Planning

Estimate the minimum launch speed needed to leave a planet or moon, useful for preliminary mission design and fuel calculations.

Example: For Earth (mass 5.972e24 kg, radius 6.371e6 m), escape velocity is about 11.2 km/s.

Astrophysics Education

Explore how escape velocity varies with mass and distance, helping students understand gravitational physics concepts.

Example: Compare escape velocities of different planets by entering their mass and radius.

Frequently Asked Questions

What is escape velocity?
Escape velocity is the minimum speed an object needs to break free from a celestial body's gravitational pull without further propulsion. This calculator computes it using the formula v = sqrt(2GM/r), where G is the gravitational constant, M is the central-body mass, and r is the distance from the center.
How do I use this calculator?
Enter the central-body mass in kilograms and the distance from the center in meters. The calculator will output the escape velocity in meters per second. Ensure you use consistent units: mass in kg and distance in m.
Does this calculator account for atmospheric drag or other forces?
No, it assumes an ideal two-body system with no other forces. It ignores atmospheric drag, solar radiation pressure, and the gravitational influence of other bodies. Real-world escape trajectories may require higher speeds due to these factors.

Tips & Common Mistakes

Tips

  • Use the mass and radius of the celestial body you're interested in. For Earth, mass is about 5.972 × 10^24 kg and radius is about 6.371 × 10^6 m.
  • Remember that distance from center is the radius if you're launching from the surface. For higher orbits, add the altitude to the radius.
  • The result is in meters per second. To convert to km/s, divide by 1000.
  • This calculator assumes a non-rotating, spherical body. Actual escape velocity can be slightly lower if you launch in the direction of the body's rotation.

Common Mistakes to Avoid

  • Using the diameter instead of the radius. The distance from center is the radius, not the diameter.
  • Forgetting to convert units. Ensure mass is in kilograms and distance in meters, otherwise the result will be incorrect.

Last updated: August 13, 2026