About the Escape Velocity Calculator
What is the Escape Velocity Calculator?
Escape velocity is the speed needed to break free of a body's gravity without further propulsion. From Earth's surface it is about 11.2 km/s – over 40,000 km/h.
Choose a body, or enter a custom mass and radius, and an altitude above the surface.
How to use the Escape Velocity Calculator
- Body (sample: Earth)
- Custom Mass (kg) (sample: 59,72,00,00,00,00,00,00,32,71,55,712)
- Custom Radius (km) (sample: 6,371)
- Altitude above the Surface (km) (sample: 0)
- Press Calculate Escape Velocity (results also refresh as you type). The result card shows the Escape Velocity, along with In km/h, Circular orbit speed at that distance and Gravity at that distance.
Formula used
v_esc = √(2GM ÷ r)
- Circular orbit speed = √(GM ÷ r) = v_esc ÷ √2
- r = distance from the body's centre
Escape velocity does not depend on the mass of the escaping object.
Worked example
These are the sample values already filled in the calculator above, and the result it returns for them:
| Input | Sample value |
|---|---|
| Body | Earth |
| Custom Mass (kg) | 59,72,00,00,00,00,00,00,32,71,55,712 |
| Custom Radius (km) | 6,371 |
| Altitude above the Surface (km) | 0 |
| Result | Value |
|---|---|
| Escape Velocity | 11.186 km/s |
| In km/h | 40,270 km/h |
| Circular orbit speed at that distance | 7.91 km/s |
| Gravity at that distance | 9.82 m/s² |
Tips for using the Escape Velocity Calculator
- Rockets do not need to reach escape velocity instantly; continuous thrust also works.
- Launching eastward near the equator, as from Sriharikota, gains extra speed from Earth's rotation.