Logarithm Calculator

Natural and common logarithms

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📖 How to Use

  1. Enter a positive number
  2. Optionally enter a custom base
  3. Click Calculate to see ln, log₁₀, log₂, and custom-base logarithms

📐 Formula

ln(x) = logₑ(x)
log₁₀(x) = log(x)
logₐ(x) = ln(x)/ln(a)

❓ FAQ

What happens if I enter a negative number?
Logarithms require positive inputs. A negative number will show an error message.

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About Logarithm Calculator

This tool is completely free, no registration required. Works directly in your browser. Supports both PC and mobile devices.

Logarithm Calculator is a free online tool that works on both PC and mobile. No registration or download required — just open in your browser. Results are accurate and reliable for everyday use and professional reference.