How many light-years away from earth is Pluto?
The average distance between Earth and Pluto is same as average distance of Pluto from the Sun. This is 0.000628 light years, nearly.
The average distance obetween two planets is nearly the average distance of the outer planet from the Sun. Earth is inner to Pluto. Average Sun-Pluto distance = 5906.4 million km. Divide by 149597870 to get distance in Au. Further divide by 62900 to get distance in ly.