Astronomy & Space
Planet Orbital Period Calculator
Kepler's Third Law states that the square of an orbit's period is proportional to the cube of its semi-major axis. This lets us calculate how long any body takes to orbit the Sun given its average distance.
T² = a³ | T (years) = a^1.5 | a in AU (1 AU = Earth–Sun distance)
Orbital Period
Semi-Major Axis—
Period (Earth years)—
Period (Earth days)—
Orbital Speed (est.)—
Solar System Reference
| Planet | Semi-Major Axis (AU) | Period (days) | Orbital Speed (km/s) |
|---|---|---|---|
| Mercury | 0.387 | 88.0 | 47.4 |
| Venus | 0.723 | 224.7 | 35.0 |
| Earth | 1.000 | 365.25 | 29.8 |
| Mars | 1.524 | 686.97 | 24.1 |
| Jupiter | 5.203 | 4331 | 13.1 |
| Saturn | 9.537 | 10747 | 9.7 |
| Uranus | 19.19 | 30589 | 6.8 |
| Neptune | 30.07 | 59800 | 5.4 |