Factorial Calculator
Calculate n! for any integer using big-int math that handles very large numbers precisely. Shows the full expanded result — useful for combinatorics, statistics, and algorithm analysis.
12!
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How to use the factorial calculator
Enter a non-negative integer. We compute n! using bigint arithmetic so even 100! returns the exact value (158 digits).
Formula & explanation
n! = n × (n−1) × … × 2 × 1, with 0! defined as 1.
Examples
5! = 120. 10! = 3,628,800. 20! ≈ 2.43 × 10¹⁸.
Frequently asked questions
- Maximum n?
- We cap at 1000 to keep the page responsive — larger values are computable but the result becomes thousands of digits.
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