Logarithm Calculator
Find the logarithm of a positive number to any positive base.
Calculate
Enter your values below.
Result
Logarithm
0
Formula used
logbase(x) = ln(x) ÷ ln(base)
Example: log₁₀(1000) = 3.
How to use this calculator
- Enter Number, Base.
- Press Calculate to see your result instantly.
FAQ
Frequently asked questions
Why must the number be positive?
Logarithms are only defined for positive numbers in the real number system.
Why must the base be positive and not 1?
A base of 1 or less doesn't produce a valid, unique logarithm scale.
How do I calculate a natural log?
Use base e (approximately 2.71828), or use the dedicated Natural Log Calculator.
What is log base 10 commonly used for?
It's used in the Richter scale, pH scale, and decibel measurements, among others.