Logarithm Calculator

log base 10, ln (natural log), log₂, and arbitrary-base logarithms — plus antilog.

Calculator Numbers & Math Updated Apr 19, 2026
X Facebook LinkedIn Reddit Email
Inputs
Presets
Results

Show Work

Enter values to see the step-by-step calculation.

Formulas

Change of base
log_b(x) = ln(x) / ln(b)
Antilog
10^x or e^x or b^x
Product rule
log(ab) = log(a) + log(b)
Power rule
log(a^n) = n · log(a)

About the Logarithm Calculator

The Logarithm Calculator is a simple, free helper for everyday maths and number work that runs entirely on your own device. log base 10, ln (natural log), log₂, and arbitrary-base logarithms — plus antilog.

How it works

Enter your figures and the result appears instantly, updating the moment you change anything. There is no submit button and nothing to wait for, so it is easy to try a few what-if numbers and compare the results. Just check each box holds the kind of value it expects.

Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.

Frequently Asked Questions

How do I use the Logarithm Calculator?

Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.

Does it cost anything or need an account?

No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.

Is anything I type uploaded?

No. The tool works entirely on your device, so the values you enter never leave your browser.

Common Use Cases

Try different numbers

Change one thing and watch the answer change. It is an easy way to compare your choices.

Nothing to set up

Open the page and start. There is nothing to install, and no account to make.

Check your work

Worked it out yourself? Use the Logarithm Calculator to make sure your answer is right.

Stays on your device

Your inputs never leave the browser — nothing is uploaded, logged, or stored anywhere.

Last updated: