Calculate the logarithm of a number in any base. One click for the common bases 10, e (natural log) and 2.
A logarithm answers the question: to what power must the base be raised to get this number? For example log base 10 of 1000 is 3, because 10 to the power 3 is 1000.
Base 10 is the common log, used in science and engineering. Base e (about 2.718) is the natural log, written ln, common in maths and growth problems. Base 2 is used in computing and information theory. The preset buttons switch between them.
No power of a positive base ever produces zero or a negative number, so the logarithm of zero or a negative value does not exist in the real numbers.