Orbital Period Calculator
Kepler's third law for any orbit.
Enter your values
Enter the orbital radius in km.
Enter the central body mass in kg.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Orbital period
- 97.14 minutes
- Period in hours
- 1.619
- Orbital velocity
- 7.546 km/s
- Orbits per day
- 14.82
Quick answer
Orbital period grows with the three-halves power of orbital radius.
T = 2π√(r³ ÷ GM)
At a glance
| What it does | Kepler's third law for any orbit. |
|---|---|
| Category | Science |
| Inputs needed | Orbital radius, Central body mass |
| Main output | Orbital period |
| Formula | T = 2π√(r³ ÷ GM) |
| Cost | Free — no sign-up, no download |
How to use the Orbital Period Calculator
- 1Enter the orbital radius from the body's centre.
- 2Enter the central body's mass.
- 3Read period and velocity.
Inputs explained
- Orbital radius(km)
- Enter the orbital radius in km.
- Central body mass(kg)
- Enter the central body mass in kg.
Worked example
Using the values the calculator loads with:
Inputs
- Orbital radius7000 km
- Central body mass5.972e24 kg
Results
- Orbital period97.14 minutes
- Period in hours1.619
- Orbital velocity7.546 km/s
- Orbits per day14.82
Frequently asked questions
What is low Earth orbit period?
About 90 minutes at 400 km altitude.
Does satellite mass matter?
No — orbital period is independent of the orbiting body's mass.
What do I need to enter into the Orbital Period Calculator?
Just 2 values: orbital radius, central body mass. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Orbital Period Calculator work out the answer?
Orbital period grows with the three-halves power of orbital radius. It applies the formula T = 2π√(r³ ÷ GM) and shows the working so you can check each step by hand.
Is the Orbital Period Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.