Size and mass values sourced from NASA Planetary Fact Sheet (Williams, 2024). All ratios are relative to Earth = 1.

Planet Size Comparison

Compare mean equatorial diameters, masses, and volumes relative to Earth—interactive charts, NASA-style reference data, shareable links. All in your browser.

By Muhammad Abdullah Rauf · Founder, EverydayTools.proUpdated 2026-06-02· Reviewed by EverydayTools Editorial Team

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Frequently Asked Questions

What does this planet size comparison show?

Mean equatorial diameters in kilometers and miles, diameter ratios versus Earth, and approximate volume ratios (diameter cubed vs Earth) for Mercury through Pluto. It compares how wide each world is—not how far it orbits from the Sun.

Is planet size the same as distance from the Sun?

No. Orbital distance (semi-major axis) is how far a planet’s path sits from the Sun in AU or km. Physical size is the planet’s own diameter. Our Planet Distance Converter handles orbits; this page handles globe size.

Why are gas giant diameters approximate?

Jupiter, Saturn, Uranus, and Neptune are oblate and lack a sharp solid surface. Published diameters are reference values (often 1-bar atmosphere or mean spherical equivalents) suitable for classroom comparison—not millimeter-precise geodesy.

How do you get volume vs Earth?

We assume each body is a sphere with the listed mean equatorial diameter, so volume scales as diameter cubed. That is a geometry teaching shortcut—real interiors, compression, and shape differ, especially for small worlds like Pluto.

Can I share a comparison between two planets?

Yes. The URL updates with your two selections (and you can use Swap). Copy the link from your browser or use the copy-summary control on the page to grab text plus the shareable URL.

How many Earths fit inside Jupiter by volume?

Using a simple sphere model with mean equatorial diameters, Jupiter’s volume is on the order of 1,300–1,400 Earth volumes (because volume scales with diameter cubed and Jupiter is about 11× wider than Earth). The exact headline number depends slightly on which reference diameters you use—this page shows the ratio from our rounded fact-sheet values.

Which planet is closest in size to Earth?

Venus is closest in diameter—only slightly smaller than Earth. Mars is about half of Earth’s width. Mercury is smaller still. For a quick side-by-side, pick Earth and Venus in the selectors above.

Why is Uranus sometimes listed as bigger in diameter than Neptune?

Mean equatorial diameter references can differ slightly between sources and update as measurements improve; Uranus and Neptune are very close in size. Mass is a different story—Neptune is denser and more massive than Uranus even when diameters are similar.

Is Pluto smaller than Earth’s Moon?

Yes—Pluto’s mean diameter is roughly 2,380 km while the Moon is about 3,470 km across, so the Moon is noticeably wider. Pluto is still a fascinating dwarf planet for comparisons; use the table on this page to see both in context with the classical planets.

Are my selections uploaded to a server?

No. Comparisons and share URLs are processed locally in your browser. EverydayTools does not receive your planet picks or store them on a server.

How much bigger is the Sun than Earth?

The Sun’s photospheric diameter is about 109 times Earth’s—roughly 1.39 million km versus 12,756 km. In a sphere model, more than one million Earth volumes could fit inside the Sun.

Is Mars bigger than Earth?

No. Mars is about half Earth’s equatorial diameter (~6,792 km vs ~12,756 km) and has far less mass and volume.

What is the largest planet in the Solar System?

Jupiter is the largest planet by diameter and mass—about 11× wider than Earth and roughly 318 Earth masses.

How do Earth and Venus compare in size?

Venus is the closest planetary match to Earth in diameter—only a few hundred kilometers narrower—making it a near-twin in scale but not in environment.

Privacy, accuracy, and trust

Privacy

Planet Size Comparison (/planet-size-comparison) runs in your browser when supported—inputs are not uploaded to EverydayTools servers.

Accuracy

Size and mass values follow NASA Planetary Fact Sheet style references (Williams, 2024). Ratios are relative to Earth = 1. For mission design, use official ephemerides.

Educational astronomy only—not for navigation, spacecraft sizing, or engineering tolerances.

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Reviewed by EverydayTools Editorial Team on 2026-06-02.