Math
Factorial Calculator
Work out the factorial of a whole number, the product of all positive whole numbers up to it.
Formula
Factorial n! = 1 × 2 × 3 × ... × n, and 0! = 1 by definition.
How it works
Enter a whole number from 0 to 170. The calculator multiplies every whole number from 1 up to your number. For example, 5! = 120.
FAQs
What does the Factorial do?
It takes the values you enter and works out the factorial for you, showing the result straight away.
What should I enter?
Enter ordinary numbers in the boxes above. If a value does not make sense for this calculation, the page will ask you to check it instead of showing a wrong answer.
Can I use the result for homework or everyday maths?
Yes. It is a general-purpose maths helper; for exam or professional work, still check the steps against your own working.