Orbital Speed Calculator
🪐 Gravity & circular motion. Use the Orbital speed formula to find orbital speed, planet mass, orbit radius: pick the value you want, type the others, and the answer updates as you go.
Default: the International Space Station, 420 km up.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Orbital speed | m/s |
| Planet mass | kg |
| Orbit radius | m |
Worked example
Find the orbital speed when Planet mass = 5.97 × 10²⁴ kg, Orbit radius = 6.79 × 10⁶ m.
Using v = √(GM/r): Orbital speed = 7660.3 m/s.
Frequently asked questions
What is the formula for Orbital speed?
v = √(GM/r). Default: the International Space Station, 420 km up.
What do the letters stand for, and what units are used?
Orbital speed in m/s, Planet mass in kg, Orbit radius in m.
How do you calculate orbital speed?
Put the values into v = √(GM/r). For example, with Planet mass = 5.97 × 10²⁴ kg, Orbit radius = 6.79 × 10⁶ m, orbital speed = 7660.3 m/s.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (orbital speed, planet mass, orbit radius) and fill in the others: it rearranges the formula for you.
