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Logarithm Calculator

Compute logarithms in any base, natural and common logs, and exponentials.

Logs and exponentials

Result: —
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For logarithms the second box is the number; for the exponential it is the power.

How to use the Logarithm Calculator

  1. Choose the type of logarithm or exponential you need.
  2. Enter the number and, when required, the base.
  3. Read the result and the check line underneath.

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Frequently Asked Questions

Common questions about the free online logarithm calculator.

Pick the type of calculation, enter the number and, when it is needed, the base, then read the result instantly.
A logarithm answers the question of what power the base must be raised to in order to produce the given number.
Yes. Any positive base other than one works, and the tool also handles natural logs and base ten logs directly.
Logarithms are only defined for positive numbers, so entering zero or a negative value shows undefined.
For example the logarithm of 8 in base 2 is 3, because 2 raised to the power 3 equals 8 exactly.
No. Everything is computed locally in your browser and nothing you enter is ever sent to a server.
Yes. The calculator is responsive and works in any modern browser on a phone, tablet or desktop.
Yes. It is completely free with no account, no sign-up and no limit on how often you use it.

Last updated: October 10, 2026