What is the average size of a star?

Answer 1

From
http://www.spacetoday.org/Questions/StarAverageSize.html

Q. What is the average size of a star? — Zachary V.

A. We really don't know if there is an "average" size.
A star is a sphere of hot glowing gas, a single ball of fire in space, often millions of miles in diameter. Stars differ in size, brightness and color.

Some stars are very young; some are very old. Some are very far away; some are closer. Some are very big; some are very small. In fact, some as small as one-tenth the size of our Sun while a couple have been found that are 100 to 200 times bigger than the Sun.

Stars are a long way off, yet all stars visible from Earth, even with the best telescopes, are within our own Milky Way galaxy. Proxima Centauri, the star nearest Earth, is so far away it's only a pinpoint of light in the largest telescopes on Earth.

There are countless stars in the Universe. Our Sun is one star among 100 billion stars in our Milky Way galaxy, alone. The Milky Way is a flat disk-shaped spiral galaxy 100,000 lightyears in diameter with a bulge at the center, like a huge blazing pinwheel of stars floating through space.

A galaxy is a vast island of stars floating through the Universe — a cloud of millions or billions of stars attracted to each other and held close by their gravity, while floating as a group through the Universe. There seem to be more galaxies strewn across the Universe than grains of sand on a beach. In fact, there are untold trillions of galaxies strewn across the Universe. Imagine the total number of stars in all of those galaxies!

Answer 2

Pretty small. Most stars are red dwarfs, which are generally around 200,000 to 400,000 miles across, so the average steller size would be around half that of our sun or 400,000 miles, give or take.