Factorial calculator
Compute factorials instantly, from 0! to 500! with exact results using BigInt.
Factorial calculator
A factorial is the product of all positive integers up to a given number: 5! = 5 × 4 × 3 × 2 × 1 = 120. This calculator computes factorials instantly from 0 to 500, showing you the exact result one number at a time. No approximation, no loss of precision — every digit is calculated correctly using BigInt arithmetic.
Use it for combinatorics problems, probability calculations, or whenever you need to find how many ways there are to arrange items. For example, 10! tells you how many different ways you can arrange 10 objects in a line. The tally shows you how many digits are in the result, which grows dramatically as the number increases: 100! has 158 digits, and 500! has 1135 digits.
Everything runs entirely in your browser — no network requests, no server computation, just pure client-side math. The result is displayed as plain text so you can copy it, download it, or paste it elsewhere. Enter any whole number from 0 to 500 and the calculator handles it instantly.
Factorials appear in formulas for permutations, combinations, and probability: choose n from a set and the number of ways grows factorially. This tool makes those calculations quick and exact, whether you are checking homework, solving a statistics problem, or exploring number patterns.