What Is the Largest Planet in the Solar System?
Jupiter is the largest planet in the solar system, with a radius of 43,441 miles. That is more than 10 times Earth's 3,359-mile radius, but it is also about 16 times smaller than the Sun's radius. Mercury is the smallest planet in the solar system with a radius of 1,516 miles.
Keep in mind that when planets are compared by radius, it tends to understate the immense difference in size. Small differences in the radius of a sphere correspond to enormous differences in total volume. Three Earths could fit inside Jupiter's famous red spot alone, and 1,400 Earths could fit inside the entire planet.