Factorial Calculator
Calculate n! for whole numbers from 0 to 170.
Tool inputs stay in your browser · optional AI search sends your query
Good to know: n! is the product of integers 1 through n; 0! = 1. Above 170, factorial exceeds ordinary JavaScript finite numbers. Results use floating-point arithmetic. All calculations stay in your browser.
How to use it (step by step)
- 1Fill in the boxes: “Whole number”. Example numbers are already there so you can see how it works; replace them with yours.
- 2The result updates instantly as you type (on a phone it is below the boxes).
- 3The bold line is the main answer. Tap Copy next to any value to copy it.
Words to know
- Factorial / permutation / combination
- Ways to count arrangements. 5! = 5×4×3×2×1. Permutations care about order; combinations do not.
- Daily rate factor (261 / 313 / 365)
- The number of paid days in a year your company uses to turn a monthly salary into a daily rate: 261 for Mon–Fri, 313 for Mon–Sat, 365 if rest days and holidays are paid too.
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