Astronomy

Orbital Period Calculator

Calculate orbital period from semi-major axis using Kepler’s third law in solar-system units.

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Orbital Period Calculator is an educational astronomy tool for exploring a standard quantitative relationship.

How it works

Enter the requested values using the stated units. The calculator validates the numerical domain and applies P² = a³.

The formula

P² = a³

Variables: a = Semi-major axis (AU).

Worked example

Example: a = 1 AU → P = 1 year.

Frequently asked questions

What is this astronomy calculator intended for?

It is intended for astronomy study, classroom exercises and understanding the quantitative relationship represented by the model.

Does the result represent every real astronomical situation?

No. Astronomy formulas often rely on simplifying assumptions, approximations or specific unit conventions. Interpret the result within the stated model.

Last content reviewSeptember 25, 2026
Editorial reviewHe-Sab Editorial Review

Sources and references

These sources are used to verify terminology, formulas, and information related to this calculator.