Log Calculator: The Complete Guide
Compute a logarithm in any base. Enter a value and a base to get the logarithm, and see the natural log (ln), common log (base 10), and binary log (base 2) alongside.
Who the Log Calculator is for
Students and engineers computing logarithms for math, science, and information theory.
How to use the Log Calculator
- Type your values into the fields above — pick your currency or units where the calculator offers them.
- Results update automatically as you type; there's no submit button and nothing is sent to a server.
- Adjust any input to compare scenarios, then copy the result with a single click.
How it works
log base b of x = ln(x) ÷ ln(b), using the change-of-base rule. The calculator also reports ln (base e), log₁₀, and log₂ for the same value.
Features
- Logarithm in any base
- ln, log₁₀ and log₂
- Change-of-base rule
- Instant result
What a logarithm is
A logarithm answers 'to what power must the base be raised to get this value?' — the inverse of an exponent. Base 10 (common log) suits orders of magnitude, base e (natural log) appears in growth and calculus, and base 2 is used in computing and information theory.