∑ Math and geometry

Logarithm calculator

Calculate the logarithm of a positive number in a chosen base.

Rules reviewed: 2026-10-13BS / EN
01

Your inputs

Starting values are an example. Replace them with your own.

Your inputs stay in your browser.

02

Your result

Enter your details and run the calculation.

METHOD

How it is calculated

log_b(x) = ln(x) / ln(b), x>0, b>0 and b≠1.

TRACEABLE

Sources and validity

Basic arithmetic or geometry using the formula shown. Uses only your inputs.

How we maintain data ↗