The distance modulus is the difference between the apparent magnitude (m) of an astronomical object, such as star, and its absolute magnitude (M). The distance modulus is given by

 

    m - M = 5 log d – 5

 

where d is the distance in parsecs.

 

Rearranging this enables d to be calculated from the formula

 

    d = 10^{(m – M + 5)/5}