Reference · Solar system scale
Planet sizes and distances compared
The planets differ enormously in size, and the distances between them are far larger than most pictures suggest. The tables below use NASA reference values; the 3D explorer can show the same proportions with its Real sizes, Real distances and True scale settings.
View the solar system to scale in 3DHow to use the explorer
Planet sizes, distances and years
| Planet | Diameter (km) | Earth = 1 | Mean distance from Sun (million km) | AU | Orbital period | Sunlight travel time |
|---|---|---|---|---|---|---|
| Mercury | 4,879 | 0.38 | 57.9 | 0.39 | 88.0 days | 3.2 min |
| Venus | 12,104 | 0.95 | 108.2 | 0.72 | 224.7 days | 6.0 min |
| Earth | 12,756 | 1.00 | 149.6 | 1.00 | 365.2 days | 8.3 min |
| Mars | 6,792 | 0.53 | 228.0 | 1.52 | 687.0 days | 12.7 min |
| Jupiter | 142,984 | 11.21 | 778.5 | 5.20 | 11.9 years | 43.3 min |
| Saturn | 120,536 | 9.45 | 1,432.0 | 9.57 | 29.4 years | 1.3 h |
| Uranus | 51,118 | 4.01 | 2,867.0 | 19.16 | 83.7 years | 2.7 h |
| Neptune | 49,528 | 3.88 | 4,515.0 | 30.18 | 163.7 years | 4.2 h |
Diameters are equatorial. One astronomical unit (AU) is Earth’s mean distance from the Sun, about 149.6 million km. Sunlight travel time is the mean distance divided by the speed of light.
Planet data quick reference
Physical data for each planet, copied from the NASA Planetary Fact Sheet (metric). A negative rotation period means the planet spins backwards (retrograde). “Length of day” is the solar day, from one noon to the next.
| Planet | Mass (1024 kg) | Density (kg/m³) | Surface gravity (m/s²) | Escape velocity (km/s) | Rotation period (h) | Length of day (h) | Mean temperature (°C) | Surface pressure (bar) | Known moons | Rings |
|---|---|---|---|---|---|---|---|---|---|---|
| Mercury | 0.330 | 5,429 | 3.7 | 4.3 | 1,407.6 | 4,222.6 | 167 | 0 | 0 | No |
| Venus | 4.87 | 5,243 | 8.9 | 10.4 | −5,832.5 | 2,802.0 | 464 | 92 | 0 | No |
| Earth | 5.97 | 5,514 | 9.8 | 11.2 | 23.9 | 24.0 | 15 | 1 | 1 | No |
| Mars | 0.642 | 3,934 | 3.7 | 5.0 | 24.6 | 24.7 | −65 | 0.01 | 2 | No |
| Jupiter | 1,898 | 1,326 | 23.1 | 59.5 | 9.9 | 9.9 | −110 | unknown | 95 | Yes |
| Saturn | 568 | 687 | 9.0 | 35.5 | 10.7 | 10.7 | −140 | unknown | 274 | Yes |
| Uranus | 86.8 | 1,270 | 8.7 | 21.3 | −17.2 | 17.2 | −195 | unknown | 28 | Yes |
| Neptune | 102 | 1,638 | 11.0 | 23.5 | 16.1 | 16.1 | −200 | unknown | 16 | Yes |
Gas and ice giants have no solid surface, so their “surface” gravity is measured at the 1-bar pressure level and NASA lists their surface pressure as unknown. Moon counts change as new moons are confirmed; the figures here match the fact sheet’s last update (18 March 2025). Want this explorer on your own page? See the embed code.
A solar system scale model: the Sun as a 1-metre ball
The Sun is about 1,391,400 km across. Shrink it to a ball 1 metre wide and keep every other size and distance in proportion:
| Planet | Model diameter | Model distance from the “Sun” |
|---|---|---|
| Mercury | 3.5 mm | 42 m |
| Venus | 8.7 mm | 78 m |
| Earth | 9.2 mm | 108 m |
| Mars | 4.9 mm | 164 m |
| Jupiter | 102.8 mm | 560 m |
| Saturn | 86.6 mm | 1,029 m |
| Uranus | 36.7 mm | 2,061 m |
| Neptune | 35.6 mm | 3,245 m |
Earth becomes a 9 mm bead on the far side of a football pitch, Jupiter is a 10 cm ball, about grapefruit-sized, 560 m away, and Neptune sits over 3 km from the ball. That is why the explorer’s default view compresses distances: at true scale, the planets would be invisible dots.
What stands out
- The inner planets are close together and small. Mercury, Venus, Earth and Mars all orbit within about 1.5 AU and their diameters added together are only about a quarter of Jupiter’s.
- The gaps grow quickly. The distance roughly doubles from Jupiter (about 5.2 AU) to Saturn (9.6 AU) to Uranus (19.2 AU), and Neptune lies at about 30 AU.
- Years get very long. Mercury circles the Sun in 88 days; Neptune needs about 164 years.
- Venus and Earth are near twins in size, while Uranus and Neptune are a similar pair of ice giants about four times wider than Earth.
Frequently asked questions
Which planet is the biggest?
Jupiter. Its equatorial diameter is about 142,984 km, roughly 11 times Earth’s.
Which planet is the smallest?
Mercury, with a diameter of about 4,879 km, about 38% of Earth’s.
Why are solar system models not to scale?
At true scale the planets are tiny compared with the gaps between them. If the Sun were a 1-metre ball, Earth would be a 9 mm bead about 108 m away and Neptune would be about 3.2 km away, so a scale model rarely fits on a page or a screen.
How long does sunlight take to reach each planet?
About 3.2 minutes to Mercury, 8.3 minutes to Earth and about 4.2 hours to Neptune.
Source: NASA Planetary Fact Sheet (diameter, distance, orbital period, mass, density, gravity, escape velocity, rotation, day length, temperature, pressure, moons, rings) and NASA Sun Fact Sheet. Model values are calculated from these figures and rounded.