About the Log Calculator
Calculate logarithms in base 10, base e (natural log, ln), base 2 or any custom base, with the change-of-base formula.
Also known as: logarithm calculator, ln calculator, natural log calculator, log base 2, log base 10, antilog.
How to use this calculator
- Enter number (x), base.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Open “Step-by-step” to see how the answer was worked out.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
log_b(x) = ln(x) / ln(b)
Worked example
Using the values pre-filled in the calculator above:
- Number (x) = 1,000
- Base: Base 10 (log)
the calculator returns:
- log10(1,000): 3
- ln(x): 6.90775528
- log₁₀(x): 3
- log₂(x): 9.96578428
Working
log_b(x) = ln(x) ÷ ln(b) = 6.90775528 ÷ 2.30258509 = 3