Where does this data come from?

Values are rounded from NASA planetary fact sheets — equatorial diameter, mass relative to Earth, mean surface gravity, mean orbital distance in AU, orbital period in Earth years, sidereal rotation period and known moon counts.

Why is Pluto included if it is not a planet?

Pluto is included as a dwarf planet for reference, clearly labelled, because it is still commonly looked up alongside the eight planets.

Which planet is the largest?

Jupiter is the largest planet, with an equatorial diameter of about 142,984 km and a mass 317.8 times Earth's — more than all the other planets combined.

Which planet has the most moons?

By this reference, Saturn leads with about 146 known moons, narrowly ahead of Jupiter at about 95. Moon counts keep rising as surveys discover more small satellites.

What is an astronomical unit (AU)?

One AU is the mean Earth–Sun distance, about 149.6 million km. Distances in the table are given in AU, so Mars at 1.52 AU is just over 1.5 times Earth's distance from the Sun.

Why is a day on Venus so long?

Venus rotates very slowly, taking about 2,802 hours (roughly 117 Earth days) for one rotation — longer in some respects than its 0.62-year orbit, and it spins in the opposite direction to most planets.

Is anything uploaded?

No — this is a static reference table that runs entirely in your browser.

What is the Planetary Data Reference?

Free reference table of planetary data — diameter, mass, surface gravity, distance from the Sun, orbital period, day length and moons for all eight planets plus Pluto. Runs entirely in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

Planetary Data Reference

Name: Planetary Data Reference
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Planetary data at a glance

A compact reference for the eight planets plus Pluto, giving equatorial diameter, mass relative to Earth, surface gravity, mean distance from the Sun in astronomical units, length of day (rotation) and number of moons. It is handy for homework, quizzes, model-building and quick fact-checks.

How it works

This is a static lookup table — type a planet name to filter it, or leave the box blank to see every body. Distances are in AU, where 1 AU ≈ 149.6 million km, and the day column is the sidereal rotation period in hours. Mass is expressed relative to Earth (Earth = 1).

Reference table

Body	Diameter (km)	Mass (Earth=1)	Gravity (m/s²)	Distance (AU)	Day (h)	Moons
Mercury	4,879	0.0553	3.7	0.39	4222.6	0
Venus	12,104	0.815	8.87	0.72	2802.0	0
Earth	12,756	1	9.81	1.00	24.0	1
Mars	6,792	0.107	3.71	1.52	24.7	2
Jupiter	142,984	317.8	24.79	5.20	9.9	95
Saturn	120,536	95.2	10.44	9.58	10.7	146
Uranus	51,118	14.5	8.87	19.20	17.2	28
Neptune	49,528	17.1	11.15	30.05	16.1	16
Pluto (dwarf)	2,376	0.0022	0.62	39.48	153.3	5

Values are rounded from NASA planetary fact sheets.

Highlighted oddities in the data

Venus’s extraordinary day

At 2,802 hours, Venus’s sidereal rotation period is longer than its year (0.62 Earth years). Venus rotates so slowly that one Venusian day is 243 Earth days — longer than its 225-day orbit. It also rotates in the opposite direction to most planets (retrograde), so the Sun rises in the west on Venus.

Mercury’s day and year near-resonance

Mercury’s 4,222.6-hour day represents a 3:2 spin-orbit resonance with its year — it completes exactly 3 rotations for every 2 orbits. For decades it was thought to be tidally locked (1:1), but radar measurements in the 1960s showed the 3:2 pattern.

Saturn’s deceptive gravity

Saturn has a mass 95 times Earth’s yet surface gravity of only 10.44 m/s² — barely above Earth’s 9.81. The reason is Saturn’s enormous volume and low average density. Saturn is the least dense planet in the solar system; it would theoretically float in a body of water large enough to hold it.

Neptune’s moon count versus Uranus

Neptune’s moon count (16) is surprisingly lower than Uranus (28), even though Neptune is slightly more massive. This reflects discovery history and the difficulty of observing distant objects, not a fundamental physical difference.

Example lookup

Looking up Mars: a diameter of 6,792 km (about half Earth’s), 0.107 Earth masses, gravity of 3.71 m/s² (about 38% of Earth’s), at 1.52 AU from the Sun, with a 24.7-hour day and 2 moons (Phobos and Deimos). For comparison, a 70 kg person would weigh about 26.7 kg on Mars.

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