Logarithm Calculator
Compute logarithms for any positive number with any base. Defaults to base 10 but supports natural log (e), base 2, and any custom base.
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Logarithm
Enter values to calculate
How to Use the Logarithm Calculator
1
Enter the number you want the log of.
2
Enter the base (default is 10).
3
See the logarithm result.
Frequently Asked Questions
What is a logarithm?
A logarithm answers: to what power must the base be raised to produce a given number? log_b(x) = y means b^y = x.
What is the difference between log and ln?
log typically means base 10 (common log), while ln means base e (natural log, approximately 2.718).
Can I calculate log of negative numbers?
Real logarithms are only defined for positive numbers. Negative inputs require complex numbers.