What is the diameter of the Sun?

The diameter of the sun is approximately 864,938 miles, though there is a slight difference between its polar and equatorial diameters. As the sun is nearly in the shape of a perfect sphere, this diameter difference is only about 6.2 miles.

The sun's star classification sets its as a G-type main-sequence star. This technically makes it a G dwarf or yellow dwarf star. There are other stars in the galaxy that are much larger than the sun. Betelgeuse, for example, is a red giant star that is approximately 14,000 times brighter and 700 times larger than the sun. The sun will grow in size as it becomes older until it starts collapsing into a white dwarf star once all the hydrogen in its center is used up.