What is escape velocity?

Escape velocity is the minimum speed an object must reach at the surface of a body to escape its gravitational field without any additional thrust. Once at this speed, the object can travel to infinity against gravity using only its initial kinetic energy.

What formula is used?

The escape velocity formula is v = sqrt(2GM/r), where G is the gravitational constant (6.674 × 10⁻¹¹ N·m²/kg²), M is the body's mass in kilograms, and r is its mean radius in meters.

Does escape velocity depend on the direction of launch?

No. Escape velocity is the same in every direction, assuming no atmosphere. In practice, rockets launch vertically to minimize time spent in the dense lower atmosphere, then turn to gain orbital speed.

Why is Earth's escape velocity about 11.2 km/s?

Earth's mass (~5.97 × 10²⁴ kg) and radius (~6,371 km) combine to produce an escape velocity of about 11.19 km/s (roughly 40,270 km/h). Real rockets exceed this speed during trans-lunar or interplanetary burns.

Can escape velocity exceed the speed of light?

Yes — this is the definition of a black hole. When the escape velocity at the Schwarzschild radius equals the speed of light (299,792 km/s), not even light can escape. The Newtonian formula shown here breaks down at relativistic speeds.

How does the Moon compare to Earth?

The Moon's escape velocity is only about 2.38 km/s — less than a quarter of Earth's. This is why the Apollo lunar module could reach lunar orbit with a relatively small ascent engine.

Escape Velocity Planet Calculator

Name: Escape Velocity Planet Calculator
Availability: InStock
Author: Nham Vu

Select a Solar System body or enter custom mass and radius to instantly calculate its escape velocity.

Select a Body

Solar System Preset

Mass (kg)

Use scientific notation: 5.972e24

Mean Radius (km)

Formula: v = sqrt(2 G M / r)
G = 6.674 × 10⁻¹¹ N·m²/kg²

Select a body or enter custom values, then click Calculate.

Earth

— km/s

Escape Velocity

vs. Earth (11.19 km/s)

Kilometers / second

Meters / second

Miles per hour

Input Values Used

Mass:

Radius:

Solar System Comparison

Body	Escape Velocity	Bar

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Summary

Select a Solar System body or enter custom mass and radius to instantly calculate its escape velocity.

How it works

Pick a preset body from the Solar System list, or choose "Custom" to enter your own values.
For custom input, enter the body's mass in kilograms and its mean radius in kilometers.
The calculator applies the escape velocity formula: v = sqrt(2 × G × M / r).
Results are shown in km/s, m/s, and mph for easy reference.
A comparison bar shows how the result stacks up against Earth's escape velocity (11.19 km/s).

Use cases

Understand how much fuel a rocket needs to leave different planets.
Compare escape velocities across the Solar System for physics lessons.
Model hypothetical planets or moons for science fiction world-building.
Illustrate why the Moon is easier to launch from than Earth.
Demonstrate the relationship between mass, radius, and gravity in class.
Calculate escape velocity for custom dwarf planets or exoplanet candidates.
Explore why black holes have escape velocities exceeding the speed of light.
Prepare for astronomy quizzes or science competitions.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu