The Earth is 1 astronomical unit, which is approximately 150 million kilometers, or 93 million miles, from the sun, according to the Astronomical Union. The AU is used to describe distances that are much smaller than a light-year.
A light-year is the amount of distance that light is able to travel in a year. It only takes the light from the sun a little over eight minutes to reach the Earth, traveling a distance of 1 AU. Distances between planets and other objects in the solar system are often measured in terms of astronomical units, as they are much too small to be effectively measured in light-years.