Enter a number and a base to compute its logarithm, or use the presets for natural log and log base ten. A logarithm answers the question of what power you must raise the base to in order to get your number, so the log base two of eight is three because two cubed is eight. Logarithms turn multiplication into addition and are central to growth rates, decibels, pH, information theory, and algorithm analysis. This calculator uses the change-of-base formula so it works for any positive base other than one, and it shows the result along with a quick check that raising the base to the answer gives back your number. Type your values and the log appears instantly. Everything is computed locally in your browser, so it is fast and completely private.
The log of a number in a given base is the exponent that base must be raised to in order to reach that number, so log base 10 of 1000 is 3.
Natural log uses the base e, about 2.718, while log base 10 uses ten, and the tool supports both plus any custom base.
Logarithms are only defined for positive numbers, so zero and negative inputs have no real log.
Enter a number and a base to compute its logarithm, or use the presets for natural log and log base ten. A logarithm answers the question of what power you must raise the base to in order to get your number, so the log base two of eight is three because two cubed is eight.
Yes. Logarithm Calculator is completely free, with no sign-up and no usage limits.
Yes. Logarithm Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Logarithm Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.