Space Physics: Escape Velocity, Orbits and Gravity Explained
The physics that governs rockets, satellites and stars — gravity, escape velocity, orbital speed, surface gravity, the scale of the cosmos and the strange mathematics of black holes.
Orbital Velocity Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Orbital velocity
7.672
- In metres per second
- 7,672.3
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Orbital Velocity Calculator
The Orbital Velocity Calculator works out your orbital velocity, along with 1 related figure in an instant. Enter mass of central body and orbital radius and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the mass of central body.
- Enter the orbital radius.
- Read off your orbital velocity, together with in metres per second — the calculator updates automatically, with no button to press.
Formula
The Orbital Velocity Calculator uses the formula:
Orbital velocity = √(0.00000000006674 × Mass of central body ÷ (Orbital radius × 1000)) ÷ 1000
Worked example
For example, with mass of central body of 5,972,000,000,000,000,327,155,712 kg and orbital radius of 6,771 km, the orbital velocity is 7.672.
| Mass of central body | 5,972,000,000,000,000,327,155,712 kg |
|---|---|
| Orbital radius | 6,771 km |
| Orbital velocity | 7.672 |
|---|---|
| In metres per second | 7,672.3 |
Results are estimates for educational use, not professional advice.
Key terms explained
- Velocity
- The speed of an object in a given direction.
- Radius
- The distance from the centre of a circle or sphere to its edge.
Frequently asked questions
It is the speed needed to stay in a stable circular orbit. For a low Earth orbit it is about 7.7 km/s.
Use v = √(GM ÷ r), with G the gravitational constant, M the central mass and r the orbital radius from the centre.
Closer in, gravity is stronger, so the satellite must move faster to balance it and avoid falling.
Escape velocity is √2 times the circular orbital velocity at the same radius — about 41% faster.
Enter the mass of central body. Enter the orbital radius. Read off your orbital velocity, together with in metres per second — the calculator updates automatically, with no button to press.
Related guides
Orbital Velocity Table: Orbital velocity by Mass of central body
Reference table of orbital velocity for Orbital Velocity across a range of mass of central body values — exact, engine-computed figures you can read off at a glance.
How to Calculate Orbital Velocity: Formula, Steps & Examples
Learn how to calculate Orbital Velocity — the formula explained step by step, with worked examples and a free calculator to check your answer.