Logarithm Calculator
Find the log of a number in any base.
How this calculator works
The logarithm of x to base b is the power you raise b to in order to get x. It is calculated as ln(x) divided by ln(b). The tool also shows the natural, common and binary logs.
Frequently asked questions
What is the difference between log and ln?
Log usually means base 10. Ln is the natural log, with base e (about 2.718).
Why must the number be positive?
Logarithms of zero and negative numbers are not defined for real numbers.
Why can the base not be 1?
Any power of 1 is 1, so no power of 1 can reach other numbers.
