What is the Escape Velocity Calculator?
Calculate escape velocity for any planet or custom body with this free escape velocity calculator. Use presets for Earth, Moon, Mars, and Jupiter, or enter mass and radius or surface gravity and radius. Results in km/s and m/s with step-by-step formulas. Runs entirely in your browser with no signup.
How to use the Escape Velocity Calculator
- Choose Celestial Body, Gravity + Radius, or Mass + Radius mode.
- Select a planet preset or enter your own g, M, and r values.
- Click Calculate to get escape velocity in km/s and m/s.
- Compare the result to Earth's escape velocity (~11.2 km/s).
- Copy the full results and calculation steps.
Common use cases
- Finding Earth's escape velocity for a physics homework problem
- Comparing Moon vs Mars escape speeds for a space mission project
- Calculating vₑ from custom mass and radius for a fictional planet
Frequently asked questions
- What is the escape velocity formula?
- vₑ = √(2GM/r) = √(2gr), where G is the gravitational constant, M is mass, r is radius, and g is surface gravity. It is the minimum speed needed to escape a body's gravity with no further propulsion.
- What is Earth's escape velocity?
- Earth's escape velocity is about 11.2 km/s (11,186 m/s). Rockets need to reach roughly this speed to leave Earth orbit entirely.
- Why is Jupiter's escape velocity so high?
- Jupiter has much stronger gravity and a larger radius than Earth. Its escape velocity is about 59.5 km/s at the cloud tops — over five times Earth's.
- Can I calculate escape velocity for a custom planet?
- Yes. Use Gravity + Radius mode with surface gravity in m/s² and radius in km, or Mass + Radius mode with mass in kg or Earth masses.
