🚀 Escape Velocity Calculator
Enter a body's mass and radius (or pick a preset) to get the escape velocity — the speed needed to break free of its gravity.
Escape velocity
11.186 km/s
= 11,186 m/s · 40,270 km/h · Mach 32.612
Escape velocity is the speed needed to break free of a body's gravity without further propulsion: v = √(2GM/r), with G = 6.6743×10⁻¹¹. It's √2 times the circular-orbit speed at the same radius, and independent of the escaping object's mass. 🔒 In your browser.
How the escape velocity calculator works
Escape velocity is the minimum speed an object needs to escape a body's gravitational pull with no further propulsion, starting from its surface: v = √(2GM/r), where G is the gravitational constant (6.6743×10⁻¹¹), M the body's mass and r its radius. Notice the escaping object's own mass cancels out — a pebble and a spaceship need the same escape speed. The result is shown in km/s, m/s, km/h and Mach.
Escape velocity is exactly √2 (≈1.41) times the speed of a circular orbit at the same radius. Earth's is about 11.2 km/s; the Moon's only 2.4 km/s, which is why the lunar lander needed far less fuel to leave. It assumes a non-rotating body and ignores atmospheric drag.
Frequently asked questions
What is escape velocity?
The minimum speed needed to break free of a body's gravity without additional thrust. For Earth it's about 11.2 km/s (25,000 mph). Below that speed an unpowered object falls back or enters orbit.
How do you calculate escape velocity?
v = √(2GM/r), where G = 6.6743×10⁻¹¹, M is the body's mass in kg and r its radius in metres. The tool has presets for Earth, Moon, Mars, Jupiter and the Sun, or enter any mass and radius.
Does escape velocity depend on the object's mass?
No — the mass of the escaping object cancels out of the equation, so a marble and a rocket need the same escape speed. What differs is the energy (and fuel) required to reach that speed.
How is escape velocity related to orbital velocity?
Escape velocity is √2 times the circular-orbit velocity at the same radius. So if a low circular orbit needs ~7.9 km/s, escaping from that radius needs ~11.2 km/s.
Why is the Moon's escape velocity so much lower?
Because it has far less mass and a smaller radius than Earth, giving weaker surface gravity. Its escape velocity is about 2.4 km/s — roughly a fifth of Earth's — which made ascent from the lunar surface much easier.