Kepler's Third Law
Calculate Kepler's Third Law instantly with the exact formula and a worked example. Free online calculator — no signup, works on mobile.
Kepler's Third Law
Semi-major axisAU
Period (yrs)
1
More about: Kepler's Third Law
What it calculates
The “Kepler's Third Law” calculator computes Period (yrs) from 1 parameter: semi-major axis (AU).
An astronomy calculation for enthusiasts and scientists.
Example calculation
With parameters Semi-major axis = 1 AU the result is 1.
How to use
- Enter the parameter values — every field above is adjustable with a slider.
- The result and related metrics are calculated automatically as you type.
- Use the additional metrics shown (if any) where needed.
- Copy the result or bookmark the page.