Largest planet: The planets in order of least

The planets in order of least to most dense Did you know, while Saturn is one of the biggest planets in our solar system is it the least dense and can float on water (if there was a large enough sea to put it in)? What’s the biggest planet in the Solar System? Illustration of Jupiter © Getty. The biggest planet in the Solar System is Jupiter. It’s a bit of a brute. The gas giant weighs over double that of every other planet in the Solar System combined. The largest planet in our solar system by far is Jupiter, which beats out all the other planets in both mass and volume. Jupiter’s mass is more than 300 times that of Earth, and its diameter, at 140,000 km, is about 11 times Earth’s diameter. (Jupiter's Great Red Spot, even at its current diminished size, spans 15,900, just over a full Earth diameter.) Jupiter is 2½ times more massive than the rest of the planets in the solar system combined. Despite its bulk, though, Jupiter has a fast ... Learn how big each planet is compared to Earth and how far they orbit from the Sun. Jupiter is the largest planet, about 11 times wider than Earth, and Mercury is the smallest, about one-third the width of Earth.