Factorial Calculator
Find the factorial of a whole number, the product of every whole number down to 1.
Quick answer: enter your details below and click Calculate — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
F
Calculators
Enter your details below.
How to use
- Enter a whole number.
- Use zero if you like: zero factorial is 1 by convention.
- Calculate to see the factorial.
About this tool
Enter a whole number n and the tool multiplies every whole number from 1 up to n together. Factorials count arrangements: for example, 5 objects can be ordered in 5 factorial, or 120, different ways. The tool refuses numbers above 170, because beyond that the result exceeds what ordinary numbers in a browser can hold.
Frequently asked questions
Why is zero factorial equal to 1?
By convention, so that counting formulas work smoothly. There is exactly one way to arrange nothing, which is to leave it empty.
Why is there a limit at 170?
Beyond 170, factorials grow past the largest finite number a browser can store, so the result would come out as infinity rather than a real answer.