Quick definitions from WordNet (equivalent-binary-digit factor)
▸ noun: the average number of binary digits needed to express one radix digit in a non-binary numeration system; on the average a number that can be expressed in N decimal digits takes 3.3N binary digits
▸ noun: the average number of binary digits needed to express one radix digit in a non-binary numeration system; on the average a number that can be expressed in N decimal digits takes 3.3N binary digits