Escape Velocity Calculator
How fast would you need to go to leave forever?
See exactly how fast you'd need to travel to break free of any planet, moon or the Sun's gravity forever — using the real physics formula v = √(2GM/r). Compare Earth's 11.2 km/s, the Moon's gentle 2.38 km/s, Jupiter's crushing 59.5 km/s and every world in between, from the surface or any altitude. Runs fully in your browser — nothing is uploaded.
About Escape Velocity Calculator
- Adjust the starting altitude to see escape speed fall the further out you already are.
- Jump straight to a specific planet with the searchable dropdown.
- No sign-up, no app — 100% free and private, everything runs in your browser.
Escape Velocity Calculator features
- Escape velocity for every planet, the Moon, Pluto and the Sun
- The real physics formula, v = √(2GM/r), not a rough estimate
- A plain-language formula walkthrough with a worked example and diagram
- Real NASA photos related to the topic, pulled from NASA's public image archive
- Adjustable starting altitude, from the surface or from orbit
- Searchable dropdown to jump straight to a specific world
- A short fun fact for every world
- Free, key-less, and 100% client-side — nothing you enter is uploaded
How to use Escape Velocity Calculator
Set a starting altitude
Leave it at 0 km for escape velocity from the surface, or enter a height to see it from orbit instead.
Scan the results
Each card shows the exact speed needed to break free of that world's gravity forever, in km/s and km/h.
Jump to a world
Use the dropdown to scroll straight to Mars, Jupiter, the Moon or any other body.
See the pattern
Notice how much easier it is to leave small, light worlds like the Moon or Mars than giants like Jupiter or the Sun.
Frequently asked questions
What is escape velocity?
It's the minimum speed something needs — in one go, with no more push after that — to break completely free of a planet's (or star's) gravity and never fall back. Go any slower and you'll either fall back down or just end up orbiting forever instead.
What is Earth's escape velocity?
About 11.2 km/s (roughly 40,270 km/h) from the surface. That's an enormous speed to reach, which is exactly why rockets need multiple powerful stages to get there.
How is escape velocity calculated?
It comes down to two things: how much stuff (mass) the planet has, and how far away you're starting from its centre. More mass, or a shorter starting distance, means a higher escape speed. Want the exact maths? See the "How the formula works" section above — it walks through the real equation with a worked example.
Does escape velocity depend on the mass of the rocket?
No. Escape velocity depends only on the planet being left and the starting distance from its centre — not on the mass of the spacecraft, satellite, or object trying to escape. A pebble and a rocket need the same escape speed.
Why is the Moon's escape velocity so much lower than Earth's?
The Moon is far smaller and lighter than Earth, so its gravity is much weaker too (about 1/6th of Earth's pull) — which is why its escape velocity is only around 2.38 km/s, less than a quarter of Earth's 11.2 km/s.
Can anything escape a black hole?
Not once you're inside it. A black hole is, by definition, an object whose escape velocity is faster than the speed of light — and since nothing can travel faster than light, nothing (not even light itself) can ever get back out.
Is this escape velocity calculator free?
Yes — completely free, with no sign-up and no app to install. Every calculation runs instantly in your browser, and nothing you enter is stored or uploaded.
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