How Many Earths Could Fit Inside Each Planet?

How Many Earths Could Fit Inside Jupiter?

Jupiter is the largest planet in our solar system, with a volume equivalent to approximately 1,321 Earths. Its mean diameter is about 139,822 km, compared with Earth’s 12,742 km. That makes it roughly 10.97 Earth diameters across. Cubing that unrounded diameter ratio gives the much larger volume ratio.

The familiar “about 1,300 Earths” is a useful rounded description. It does not mean Jupiter is 1,300 times wider, and it does not measure its mass. Unlike the rocky Earth, Jupiter has an enormous envelope dominated by hydrogen and helium. Comparing their volumes describes the space enclosed by their reference boundaries, rather than how much material of the same density they contain.

Select Jupiter in the explorer to see why Earth looks so small beside it. Both disks share one diameter scale, so their relative widths remain correct as you switch planets.

How Many Earths Could Fit Inside Saturn?

Saturn’s volume is approximately 764 Earth volumes, with a mean diameter near 116,464 km. Its famous rings are excluded: measuring the width of the rings would answer a different question from measuring the planet itself.

A large volume does not require a high average density. NASA describes Saturn as mostly hydrogen and helium, with an average density lower than water’s. It also has no solid surface to stand on. Its huge envelope occupies a great deal of space, while its mass per unit volume is much lower than Earth’s.

This is one reason planetary size and the strength of surface gravity do not follow a simple volume ranking. Gravity depends on mass and distance from the center. Explore your weight on each planet to compare that separate physical quantity.

How Many Earths Could Fit Inside Uranus and Neptune?

Uranus has approximately 63.1 Earth volumes; Neptune has about 57.7. Their diameters are each close to four Earth diameters. Four cubed is 64, so a volume near sixty Earths is consistent with what looks like a much smaller difference in width.

Uranus and Neptune are classified as ice giants, while Jupiter and Saturn are gas giants. The distinction concerns composition and internal structure, rather than a frozen outer surface. NASA’s Uranus facts describe a large proportion of hot, dense material containing water, methane and ammonia beneath a gaseous atmosphere. “Ice” in this classification does not mean that visitors would find an ordinary solid ice sheet to land on.

Uranus is slightly larger by volume than Neptune. That alone does not tell you which contains more mass or which has stronger gravity. Use the pair selector to compare their volumes directly, without having to divide the rounded table entries yourself.

What About Mercury, Venus and Mars?

Mercury contains about 0.0561 Earth volumes and Mars about 0.151. Inverting the unrounded ratios, Earth has roughly 17.8 times Mercury’s volume and 6.64 times Mars’s. A smaller rocky planet does not hold several complete Earths; its volume is only a fraction of Earth’s.

Venus is much closer to our size, at approximately 0.857 Earth volumes. A diameter only about 5% smaller than Earth’s still leads to a volume about 14% smaller. The cube law magnifies even fairly modest differences in linear size.

These inner worlds have much smaller radii than the giant planets and lack their enormous hydrogen-and-helium envelopes. Their different formation and evolutionary histories cannot be inferred from size alone. The explorer compares geometry, without assuming that the planets have the same composition.

Can You Really Fit That Many Earths Inside a Planet?

Volume equivalence and sphere packing are different problems. Imagine dividing a planet’s volume into a quantity of material equal to Earth’s volume. The ratio tells you how many such volume units there are, including fractional units. That is what the explorer calculates.

Now imagine trying to arrange rigid, non-overlapping Earth-sized balls inside a larger spherical container. Spaces remain between the balls, and the boundary constrains their arrangement. Dividing the container’s volume by a ball’s volume does not solve that packing problem. Rounding the answer down does not fix it either.

Volume grows with the cube of radius: doubling a sphere’s radius gives eight times its volume, and tripling it gives 27 times its volume. The explorer’s disks show diameter on one shared scale; the labeled Earth volumes describe the three-dimensional comparison.

Real giant planets are also not empty containers. Their hot, pressurized interiors would not preserve Earth as an intact object. This page is a mathematical comparison of planetary volumes, not a proposal for physically inserting one inhabited world inside another.

Data, Method and Sources

All eight radius inputs come from JPL’s Planetary Physical Parameters, checked October 28, 2026, reference D (Archinal and colleagues, 2018). The shared dataset uses mean, equal-volume radii in kilometers: Mercury 2,439.4; Venus 6,051.8; Earth 6,371.0084; Mars 3,389.50; Jupiter 69,911; Saturn 58,232; Uranus 25,362; Neptune 24,622.

The planet’s radius divided by Earth’s radius, cubed, gives its Earth-volume ratio. Mean diameter is twice that radius. Full input precision is retained during calculations; the display rounds diameters to kilometers, large volume ratios to whole numbers and smaller ratios to readable decimals. Earth compared with itself is exactly 1 by definition.

Planets are not perfect spheres. These equivalent spheres preserve volume, rather than equatorial shape or actual surface area. Giant-planet boundaries are atmospheric reference levels, not solid ground. Source uncertainties remain in the dataset; the displayed results are approximate rather than precision measurements. Different reference radii and rounding can explain small differences from other tables.

Spherical volume is calculated as 4πr³/3. No remote service or live astronomical data is needed for the tools. Illustrations are original stylized vectors, not photographs or maps of surface features.

Compare Planetary Days

Volume does not determine how fast a planet turns. Explore planetary day lengths to compare Jupiter’s fast rotation with slowly spinning Venus.