Planet Size Comparison

Every disc is drawn from the Diameter row of NASA's Planetary Fact Sheet, which the fact sheet's notes define as the diameter of the planet at the equator. HeightViz stores each figure once, in centimetres, and the board converts it to pixels with one shared scale, so the discs keep the exact ratios of the real bodies: Jupiter's disc is 11.21 times as wide as Earth's because its diameter is 11.21 times larger. Labels read in kilometres with a mile ruler on the right; switching the unit to ft/in swaps them.

Saturn is drawn without its rings, because the sourced figure is the planet body. The Moon and Pluto are on the board because they are in the same fact-sheet table as the planets; Pluto is marked as a dwarf planet. This is the same comparison engine that draws people, animals and buildings on the size comparison board, with kilometres and miles added for subjects this large.

In the fact sheet's own order, from the Sun outward, with the Moon beside Earth. The last column divides each diameter by Earth's.

The board opens with the eight planets. The presets under the rail swap in the rocky planets, the giant planets, Earth beside the Moon, Earth beside Jupiter, or Pluto beside the Moon. Search the catalog to add any body, drag a disc to reorder, click one to see its source, and use Share or Download to keep the board: a link restores exactly the same bodies in the same order, and a download is the board on a clean white background.

Adding a person is allowed, and the result is not a mistake. An adult of 175 cm is about one part in 7,289,143 of Earth's diameter, far less than a pixel at any scale that fits a planet on screen. The board keeps the shared scale and marks the figure as too small to draw instead of enlarging it, because a distorted scale would defeat the point of the comparison.

Only the diameter row is used. Masses, distances from the Sun, day lengths and the other rows of the fact sheet are not shown, and the Sun is not a column in the fact sheet's planet table, so it is not in the catalog. Rings, atmospheres and moons other than Earth's are not drawn. Nothing on this page is estimated or rounded beyond the figures NASA publishes; the discs are plain shapes because HeightViz draws every subject as a flat silhouette on one scale.

• NASA NSSDCA Planetary Fact Sheet — "Diameter (km)" row for Mercury, Venus, Earth, the Moon, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto; last updated 18 March 2025 (Dr. David R. Williams). The fact sheet's notes page defines the figure as the diameter of the planet at the equator. Checked 2026-09-20.