Change of base logarithm calculator
Convert log_b(x) using log_k(x)/log_k(b) for any positive bases.
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Tool guide
Change of base logarithm calculator: how it works
Practical information to understand the result and use this tool correctly.
About Change of base logarithm calculator
Any logarithm can be rewritten in another base via log_b(x)=log_k(x)/log_k(b).
This tool uses natural logs internally for numerical stability.
Requires positive x and base b ≠ 1.
How to use it
- 1Enter x > 0 and base b > 0, b ≠ 1.
- 2Calculate log_b(x).
- 3Compare with the ln ratio card.
Frequently asked questions
- Common log?
- Set base 10.
- Natural log?
- Set base e ≈ 2.71828, or use the ln tool.