Logarithm Calculator

Find the logarithm of a positive value in a valid chosen base.

Your numbers

Logarithm

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Use consistent units. The result follows the assumptions you enter.

Formula

Use log_b(x) = ln(x)/ln(b). x is a positive value and b is a positive base other than unity. ln is the natural logarithm.

Find the logarithm of a positive value in a valid chosen base.

Worked example

Value: 1000
Base: 10

Logarithm: 3

Scope and limitations

Use consistent units. The result follows the assumptions you enter.

Inputs are checked for missing values and allowed ranges. A result outside the finite numeric range is not displayed. Rounding affects display, while the calculation uses the model’s numeric precision.

Check your units and assumptions before relying on a result. Changing a label does not convert a currency or physical unit.

Formula version: ceabcd6798b7 · Example checked: 2026-10-30

Methodology