A diagram that shows the planets big enough to see cannot show the distances, and one that shows the distances honestly is an empty page with a few specks on it. Shrink the Sun to something you can hold and see where everything lands.
Nothing here is exaggerated: every disc is drawn at the same kilometres-per-pixel. Tap one to put it in the comparison below.
Four balls of rock and metal close in, two of hydrogen and helium, two of ice. The dividing line is the frost line — the distance at which water could freeze while the planets were forming, which is why the big ones are all outside it.
Balance the sunlight a planet absorbs against the heat it radiates and you get its temperature, with nothing but distance and reflectivity. It works — until a planet has air. Cyan is what the sums predict, red is what the thermometer says.
Each planet is stored as six numbers — the orbital elements — and everything you see is worked out from them. The semi-major axis and eccentricity give the shape of the ellipse; the inclination, and the two angles that orient it, tilt that ellipse in space; the mean anomaly says where along it the planet was at a known moment. To find a planet at any other moment you advance the mean anomaly and solve Kepler's equation, M = E − e·sin E, which has no closed-form solution and has to be hunted down numerically. Pluto's orbit, at an eccentricity of 0.25, is the one that makes a lazy solver work for it.
Kepler's third law: square the year, cube the distance, and the answer is the same for everything going round the Sun. In Earth years and astronomical units the constant is simply 1, which is a gift — a planet four times further out takes eight times as long. Every period on this page is computed from that law rather than looked up, and each one lands within a fraction of a per cent of the published value. Neptune is the worst at 0.02%.
If the Sun is a football, Earth is a grain of sand twenty-six metres away and Neptune is another grain most of a kilometre off. There is no page, screen or classroom wall on which the planets are both visible and correctly spaced, so every picture you have ever seen — including the default view here — cheats on one or the other. The true scale option does not cheat, and that is exactly why it looks so empty.
Orbits here are two-body ellipses around the Sun and nothing tugs on anything else. Real orbits perturb each other, and that omission is not a small one historically: Neptune was discovered in the perturbations this ignores, predicted on paper from the way Uranus was running late. Mercury's orbit precesses by an amount Newton cannot account for and Einstein can, and none of that is here either. Positions are accurate enough to draw and to show you which side of the Sun a planet is on; they are not an ephemeris and you should not point a telescope with them. Moons are compared but not orbited — they go round planets, not the Sun, and at any honest scale they would sit inside their own planet's dot.
A spinning planet is not a sphere. Jupiter's equator is 4,600 km further from its centre than its poles, so there are two honest answers to "how big is it". This page uses the mean radius throughout, because that is the one that gives the right volume and therefore the right density. It means the escape velocity here reads 60.2 km/s where most references say 59.5 — that figure is taken at the equator. Both are right; they are answers to slightly different questions, and quietly switching between them per row is how a tool ends up contradicting itself.
No changes to this tool’s own behaviour since the earliest archived release (v3.66). The full history for the site is in the changelog.