What is the Factorial Calculator?
Calculate the factorial n! of a whole number.
Enter n and the Factorial Calculator returns n! and number of digits. Results update as you type, and nothing you enter leaves your device.
How it is calculated
n! = n × (n − 1) × … × 2 × 1, and 0! = 1
How to use it
- Enter n.
- Read n! in the results panel. It updates as you type.
- Change any value to compare scenarios, or use Share to send the result as a link.
Worked example
Common questions
What formula does the Factorial Calculator use?
It uses: n! = n × (n − 1) × … × 2 × 1, and 0! = 1.
What do I need to use the Factorial Calculator?
You need n. Sensible starting values are filled in so you can see how it works straight away.
Is the Factorial Calculator free, and is my data stored?
It is free with no sign-up. The calculation runs in your browser, so the values you enter are not sent to or stored on our server.