Logarithm Calculator
Calculate common log, natural log, binary log, or any custom-base logarithm with antilog support.
Base: 10
Result
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Enter a value to see the result.
log(ab) = log(a) + log(b)Logarithm of a product
log(a/b) = log(a) − log(b)Logarithm of a quotient
log(aⁿ) = n × log(a)Logarithm of a power
logₐ(1) = 0Log of 1 is always 0
logₐ(a) = 1Log base a of a is always 1
How to use
- 1
Choose a base
Select log base 10, ln (base e), log base 2, or enter a custom base.
- 2
Enter a value
Type the number you want to find the logarithm of.
- 3
Read the result
The logarithm is displayed instantly. Toggle antilog mode to compute the inverse.
Frequently asked questions
What is the difference between log and ln?
log usually means base 10 (common logarithm), while ln means base e (natural logarithm, approximately 2.71828).
What is an antilog?
The antilog is the inverse: if log(x) = y, then antilog(y) = x. It is computed as base^y.
Can I use a custom base?
Yes. Enter any positive base (other than 1) and the tool uses the change-of-base formula.
Is my data sent anywhere?
No. All calculations run in your browser.
Compute logarithms in any base. Choose common log (base 10), natural
log (ln, base e), binary log (base 2), or enter a custom base. An
antilog mode calculates the inverse (10^x, e^x, etc.). Includes a
reference card showing the key logarithm rules. All calculations run
in your browser.