How to use the kepler's third law calculator
Find orbital period from the semi-major axis around the Sun. Enter semi-major axis in the field above; the orbital period, orbital period are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- a — Semi-major axis (AU)
Worked example
With semi-major axis = 1.524 AU, the calculator gives orbital period ≈ 1.881384 years; orbital period ≈ 687.1755 days.
Frequently asked questions
What is the formula for the kepler's third law calculation?
Orbital period (years) = a^1.5. Orbital period (days) = [Orbital period] × 365.25. Here a is semi-major axis (AU).
What inputs do I need for the kepler's third law calculator?
You need semi-major axis in AU. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.