Log Calculator

Any base — with one-tap presets for base 10, base 2, and natural log.

log2(8) =
3

A logarithm answers: "what power do I need to raise the base to, to get this value?" — it's the inverse operation of exponentiation.

A worked example

log base 2 of 8 equals exactly 3 — since 2³ = 8.

Frequently asked questions

What's the difference between log and ln?

'log' typically means base 10 by convention, while 'ln' specifically means natural log — base e (≈2.71828). Both are logarithms, just with a different base.

Why can't I take the log of a negative number or zero?

Logarithms answer 'what power gives this result' — since a positive base raised to any real power always produces a positive result, there's no real exponent that produces zero or a negative number.