Logarithm Calculator
Calculate log with any base plus natural log, log base 10 and log base 2.
log base 10
3
ln (natural log)
6.90775528
log10
3
log2
9.96578428
Enter a value and a base to get the logarithm in that base. It also shows ln, log10 and log2 side by side.
How to use
- Enter the value you want the logarithm of.
- Enter the base you want to use.
- Read the custom-base result along with ln, log10 and log2.
Frequently asked questions
- How is log with a custom base computed?
- It uses the change-of-base rule: log_b(x) equals ln(x) divided by ln(b).
- Why must the base not be 1?
- Logarithm base 1 is undefined because 1 raised to any power is always 1, so no exponent can produce other values.