Kepler Third Law Calculator
Kepler third law is one of the most elegant relationships in astronomy: for anything orbiting the Sun, the square of the orbital period in years equals the cube of the semi-major axis in astronomical units. That clean form lets you find one from the other without ever touching the mass or the gravitational constant. This calculator works both ways. Enter a period in years to get the average orbital distance in astronomical units, or enter a distance to get how many years an orbit takes. It is perfect for checking planets, asteroids and comets in our solar system, or for homework and quick sanity checks. Everything is computed instantly in your browser with no network calls.
How to use Kepler Third Law Calculator
- Choose whether you know the period or the semi-major axis.
- Enter the period in years or the axis in astronomical units.
- Read the converted value from the P squared equals a cubed relation.
Frequently asked questions
What relationship does this use for the solar system?
For orbits around the Sun, period in years squared equals semi-major axis in astronomical units cubed, so the two quantities convert cleanly without extra constants.
Can it go from distance to period and back?
Yes; enter a semi-major axis in AU to get the period in years, or enter a period to solve for the orbital distance.
Why does the simple form only work in these units?
The clean P squared equals a cubed identity holds only when period is in years, distance is in AU and the central body is the Sun, which cancels the constants.
What is Kepler Third Law Calculator?
Kepler third law is one of the most elegant relationships in astronomy: for anything orbiting the Sun, the square of the orbital period in years equals the cube of the semi-major axis in astronomical units. That clean form lets you find one from the other without ever touching the mass or the gravitational constant.
Is Kepler Third Law Calculator free to use?
Yes. Kepler Third Law Calculator is completely free, with no sign-up and no usage limits.
Does Kepler Third Law Calculator work in a web browser?
Yes. Kepler Third Law Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with Kepler Third Law Calculator?
Yes. Kepler Third Law Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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