Change-of-Base Formula :

Let a, b, and x be positive real numbers such that a ≠ 1 and b ≠ 1. Then can be converted to a different base as follows.

The logarithm expression is .

Changing Bases Using Common Logarithms:

Evaluating Common Logarithms on a Calculator :

Changing Bases Using Natural Logarithms:

Evaluating Natural Logarithms on a Calculator :

.