Log Calculator
Calculate logarithms with any base, including natural log and common log.
Results
Logarithm Result-
Natural Log (ln)-
Common Log (log₁₀)-
Inverse (b^result)-
Change of Base Formula-
What is a Log Calculator?
A logarithm calculator computes the exponent to which a base must be raised to produce a given number. It supports arbitrary bases, natural logarithms (ln), and common logarithms (log₁₀).
How to Use
- Enter the number you want to find the logarithm of.
- Enter a base or check "Use base e" for natural logarithm.
- Click Calculate to see the result, inverse, and formula used.
Frequently Asked Questions
What is the change of base formula?
log_b(x) = log(x) / log(b). It lets you calculate a logarithm in any base using natural or common logarithms.
Can the base be negative?
No. The base must be positive and not equal to 1 for real-valued logarithms.
What is the difference between ln and log?
ln is the natural logarithm with base e (~2.718). log usually refers to base 10, though in some fields it means base 2.
What is the inverse of a logarithm?
The inverse is exponentiation: if log_b(x) = y, then b^y = x.