๐Escape Velocity Calculator
Calculate the escape velocity of any planet, moon, or star โ or enter a custom mass and radius to explore hypothetical worlds.
Free Escape Velocity Calculator
Ever wondered how fast a rocket needs to go to leave Earth โ or Jupiter โ behind? Our free escape velocity calculator works it out instantly using v = โ(2GM/r), the same formula astrophysicists use. Pick a planet, moon, or the Sun from the preset list and see its escape velocity in seconds, or switch to custom mode and enter any mass and radius to explore a hypothetical world.
Results are shown in m/s, km/s, km/h, and mph, alongside a quick comparison to Earth's own escape velocity of 11.19 km/s, so you can see at a glance how much stronger or weaker a body's gravity really is.
Perfect for physics and astronomy homework, science fair projects, or just satisfying curiosity about the universe. No sign-up, no downloads, no limits. See the About page or the FAQ for more.
About the Escape Velocity Calculator
Features
Real physical data
Preset bodies use accurate published mass and radius values.
Custom mass/radius mode
Enter any mass (with scientific notation) and radius for a hypothetical body.
Multi-unit output
Results shown in m/s, km/s, km/h, and mph simultaneously.
Earth-comparison view
Every result is compared against Earth's own escape velocity of 11.19 km/s.
Frequently Asked Questions
What is escape velocity?
The minimum speed an object needs to break free of a body's gravity without further propulsion, given by v = โ(2GM/r).
How does this calculator work?
Pick a preset body or enter a custom mass and radius, and it computes the escape velocity instantly using the standard formula.
Is it free?
Completely free, no sign-up, downloads, or limits.
What is Earth's escape velocity?
About 11.19 km/s (roughly 40,270 km/h).
Can I calculate escape velocity for a custom object?
Yes, switch to custom mode and enter any mass (kg) and radius (km).
What units are the results shown in?
m/s, km/s, km/h, and mph, all calculated together.
What happens if I enter a radius of zero?
The calculator flags this as invalid input instead of returning an error or infinite value.
Does the calculator show the formula used?
Yes, the substituted formula and values are shown alongside the result.
Is my data stored?
No; everything runs in your browser and isn't stored or sent anywhere.
Does it work on mobile?
Yes, fully responsive on all screen sizes.