The question "how big is the sun?" has a couple of answers, because scientists have more than one way of measuring how "big" something is. The mass of an object tells how much matter it contains, while the volume is how much space it takes up. The Sun has a mass of nearly 2 x 1030 kilograms, which is more than 330,000 times the mass of Earth. It has a diameter of nearly 1.4 million kilometers (865,000 miles), and its volume could enclose about 1.3 million Earths.
By human standards, that’s a lot of matter. In fact, the Sun contains 99.86% of the matter in the entire solar system (Jupiter contains most of the rest). On the other hand, it’s important to remember that the Sun is a fairly average-size star. Rarely, stars may contain dozens or even hundreds of times the mass of the Sun. Size comparison videos can help visualize such massive objects.
The Sun spans about a half of a degree in the sky. Its angular size is about equal to that of the moon, because while the Sun’s diameter is about 400 times larger than the moon’s, the Sun is 400 times further from Earth.