Escape Velocity Calculator
Calculate the escape velocity from any planet, moon, or star using ve = √(2GM/R) with NASA body data and CODATA gravitational constant.
Reviewed October 7, 2026 Runs in your browser — inputs are never stored
Body presets
Formula
ve = √(2GM ÷ R) · G = 6.67430 × 10⁻¹¹ m³ kg⁻¹ s⁻²
This tool provides educational conversions of astronomical distances only. It is not a navigation, mission-planning, or ephemeris service. For professional or spacecraft work, use official IAU, NASA, or observatory data products.
About the Escape Velocity Calculator
The escape velocity calculator finds the minimum speed an object needs to escape the gravity of a planet, moon or star without further propulsion, using v = √(2GM / r), where G is the gravitational constant, M the body’s mass and r the distance from its centre. Earth’s escape velocity at the surface is about 11.2 km/s. The result ignores air resistance and is a useful way to compare how hard it is to leave different worlds.
How to use it
- 1Pick a body preset or enter a custom mass and radius.
- 2Press Calculate to get the escape velocity.
- 3Read the result in m/s, km/s, km/h, and mph.
Worked example
Earth (M = 5.972 × 10²⁴ kg, R = 6.371 × 10⁶ m) gives an escape velocity of about 11,186 m/s (11.19 km/s). The Moon's is only 2.38 km/s, which is why lunar launches need far less fuel.
How it works
The escape velocity formula
Escape velocity comes from equating kinetic energy to gravitational potential energy: ½mv² = GMm/R, giving ve = √(2GM/R). It is the speed at which an object leaves a body\'s gravity well with zero residual speed at infinity.
Reference escape velocities
- Moon: 2.38 km/s · Mars: 5.03 km/s · Earth: 11.19 km/s
- Jupiter: 59.5 km/s · Sun (surface): 617.5 km/s
Who it is for
Physics students, aerospace enthusiasts, and anyone learning how gravity binds spacecraft to planets.
Why it helps
Escape velocity is the minimum speed needed to break free from a body's gravity — a foundational concept in orbital mechanics and rocketry.
Common use cases
- Computing launch speed requirements for planets and moons
- Comparing how hard it is to leave each world
- Teaching gravitational potential energy in physics
- Sanity-checking spacecraft mission parameters
Tips for better results
- Escape velocity assumes no atmospheric drag and no other forces.
- It is the speed at the surface; you need less delta-v from higher altitudes.
- The Sun's escape velocity at its surface is about 617.5 km/s.
- Use scientific notation for large masses (e.g. 5.972e24).
Common mistakes to avoid
- Forgetting that escape velocity scales with √(M/R), not M alone.
- Ignoring atmospheric drag, which raises the real launch speed needed.
- Mixing kilometres and metres for the radius.
- Confusing escape velocity with orbital velocity (escape is √2 × circular).
Frequently asked questions
A:Escape velocity is the minimum speed an object needs, with no further propulsion, to break free from a body's gravitational pull and reach infinity with zero residual speed. It equals √(2GM/R).
A:The Moon has much less mass than Earth, so GM is smaller. Its escape velocity is about 2.38 km/s versus Earth's 11.19 km/s.
A:The formula gives the vacuum value. Real launches need extra speed to overcome atmospheric drag and gravity losses, so actual launch vehicles exceed the theoretical escape velocity.
A:Yes. It runs in your browser on CalcWisee with no sign-up required.
Reviewed for accuracy · Last updated October 7, 2026
The astronomical unit is taken as exactly 149,597,870,700 metres per the IAU 2012 definition. Related light-time and light-year factors use the defined speed of light and the IAU Julian year where applicable.
CalcWisee Editorial Team
Calculator development and formula review
CalcWisee is an independent site founded by Ayman. Every calculator is built from a published formula or official definition, tested against hand-worked examples before it goes live, and corrected promptly when a reader reports an issue to ayman@calcwisee.com.
Expertise: Financial mathematics, Health and fitness formulas, Applied mathematics, Unit conversion standards
References & sources
