Logarithm Calculator.

Calculate a logarithm for any valid positive base and argument.

On-device calculationNo signup

Set your values

Results update as you type.

02 / ANSWER

Argument (x)

Base (b)Greater than 0 and not 1

Greater than 0 and not 1

Presets

How to Use

A logarithm answers the question: what exponent on the base gives the argument? For example, log₂(8) = 3 because 2³ = 8.

For a real logarithm, the argument must be greater than 0, and the base must be greater than 0 but not equal to 1. Bases between 0 and 1 are valid and produce a decreasing logarithm.

FAQs

What is a logarithm?

A logarithm is the exponent needed to raise a base to a given positive argument. For example, log₂(8) = 3 because 2³ = 8.

Which bases are valid?

For real logarithms, the base must be positive and different from 1, and the argument must be greater than 0.

Related Calculators

Change of Base CalculatorEvaluate logarithms using any valid base.Natural Log CalculatorCalculate the natural logarithm ln(x) for a positive value.2D Distance CalculatorCalculate Euclidean distance between two points in a plane.3D Distance CalculatorCalculate Euclidean distance between two points in three-dimensional space.AAS Triangle CalculatorSolve a triangle from two angles and a non-included side using the law of sines.Absolute Change CalculatorCompare original and new values with signed, absolute, and percentage change outputs.