CalculateMeasure

Math & Geometry

Logarithm Calculator

Calculate the logarithm of a positive number for any valid positive base other than one.

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Calculator guide

How to use the Logarithm Calculator

Calculate the logarithm of a positive number for any valid positive base other than one. Enter the requested values and select Calculate. The result and supporting values are produced locally in your browser.

Formula

log_b(x) = ln(x) ÷ ln(b)

Worked example

log₁₀(1000) = 3 because 10³ = 1000.

What to keep in mind

  • The logarithm input must be positive.
  • A logarithm base must be positive and cannot equal 1.

Methodology

This calculator uses deterministic arithmetic and performs the calculation locally in your browser. Verify assumptions, units, and source values for your specific use case.

Review standard: Level A · Standard formula. How calculator reviews work.

Frequently asked questions

What does this calculator calculate?

Calculate the logarithm of a positive number for any valid positive base other than one.

How is the result calculated?

log_b(x) = ln(x) ÷ ln(b).

Can I use the result for an important decision?

Use the result as a calculation aid and verify the inputs, assumptions, and applicable professional or regulatory requirements before relying on it for an important decision.

Does CalculateMeasure store the values I enter?

The calculator performs its arithmetic in your browser. The calculator itself does not need to send your entered values to a server to produce the result.