How big is the planet Neptune?

The planet Neptune has a radius of 15,299 miles and pole radius of 15,125 miles. It has a mass of 102.4E24 kg. Neptune is the forth-largest planet by diameter and third-largest by mass. It is also the densest planet.

Neptune has an average diameter of 15,388 miles, the equivalent of 24,341 kilometers, and almost four times the size of the Earth. It is oblate spheroid in shape; the shape comes from the rotation that causes slight bulging around the equator. Neptune, which is the 8th planet from the Sun, was discovered in 1846 and named after the Roman god of the sea.