Factorial Calculator
Calculate the factorial n! of a whole number.
Worth Knowing
The factorial n! multiplies every whole number from 1 up to n, and it grows faster than almost any other elementary function — 10! is already over three million. By convention 0! equals 1, which isn't arbitrary: it's the value that keeps the combination and permutation formulas consistent. Factorials underpin most of combinatorics, but they overflow standard number precision quickly, so results beyond roughly 170! exceed what ordinary floating-point arithmetic can represent.
How to Use
- Enter n into the Factorial Calculator above.
- Your result appears instantly as you type — there's no submit button or page reload.