The Orbital Period calculator uses Kepler's Third Law to compute the period of an orbiting body based on the semi-major axis and the mass of the center body (e.g. Sun or planet).
INSTRUCTIONS: Choose units and enter the following:
Orbital Period (T): The calculator returns the period in days. However, this can be automatically converted to compatible units via the pull-down menu.
Kepler's Third Law, the orbital period `T` of two bodies orbiting each other in a circular or elliptic orbit is:
The formula and equation are from Wikipedia ().