Factorial Calculator
Calculate the factorial of any number (n!). Handles large numbers and shows the full multiplication sequence. Numbers never leave your device — every calculation runs locally in your browser.
How to Use the Factorial Calculator
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Frequently Asked Questions
What is n! (factorial)?
n! = n × (n-1) × (n-2) × ... × 2 × 1. For example, 5! = 5 × 4 × 3 × 2 × 1 = 120. By definition, 0! = 1.
How large a number can it handle?
JavaScript handles numbers up to 2^53. Factorials grow very fast — 18! is the largest exact integer factorial. Beyond that, the tool shows approximate scientific notation.
Does it show the multiplication steps?
Yes. The tool displays the full expansion (e.g., 6! = 6 × 5 × 4 × 3 × 2 × 1 = 720) so you can follow the calculation.
What are common uses of factorials?
Permutations, combinations, probability calculations, Taylor series, binomial distribution, and various mathematical formulas in statistics and algebra.
When using Factorial Calculator, is the calculation done locally?
Yes. All calculations run in your browser. No data is transmitted.
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Last updated October 2026