Planets by Orbital Period Around the Sun

About This Dataset

This chart shows how long each planet takes to complete one orbit around the Sun, measured in Earth years. Mercury races around in just 0.24 years (88 days), while Neptune needs 164.8 years - meaning it has completed only one full orbit since its discovery in 1846.

Analysis

Orbital periods grow much faster than distance from the Sun, exactly as Kepler's third law predicts: Neptune is 30 times farther out than Earth but takes 165 times longer to orbit. The inner four planets all finish a lap within two Earth years, while the outer giants live on a completely different clock - Uranus takes 84 years, so a person born there would celebrate their first birthday at the end of a long human life. Neptune, discovered in 1846, completed its first observed full orbit only in 2011. The practical consequence shapes space exploration: launch windows to Mars open every 26 months as the fast inner planets realign, while missions to the outer planets get one favorable planetary lineup every couple of decades.

Source: NASA Planetary Fact Sheet

Key Findings

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Neptune leads in Orbital Period (Earth Years) with 164.79.

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Average Orbital Period (Earth Years): 36.73 · median: 6.87.

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Gap: Neptune is 686.6× larger than Mercury.