Skip to content
Calixo

Logarithm Calculator

Find the logarithm of a number to any base.

Inputs

Saved Scenarios

— select 2+ to compare

Result

2.0000

Spark says

How it's calculated

Formula

log⁡b(x)=ln⁡(x)ln⁡(b)\log_b(x) = \dfrac{\ln(x)}{\ln(b)}
x
— The number
b
— The base

What is the Logarithm Calculator?

A logarithm answers the question: to what power must the base be raised to produce this number? This calculator computes it for any base using the change-of-base formula.

How to use it

  1. 1 Enter the number.
  2. 2 Enter the base.

Worked examples

log base 10 of 100

Result is 2, since 10² = 100.

Try it

Frequently asked questions

What is the change-of-base formula?

log_b(x) = ln(x) / ln(b) — it lets you compute a logarithm in any base using natural logarithms, which most calculators provide directly.