Math & Statistics Tools
Factorial Calculator
Calculate factorials (n!) and double factorials with big-integer support.
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What is Factorial?
n! = n x (n-1) x ... x 1. Factorials grow extremely fast. 170! is approximately 7.3e306, near JavaScript Number limit. BigInt mode supports larger values.
How it works
Iterative multiplication with BigInt support. We compute n! exactly for n up to 10000 using BigInt and display in scientific notation when too long.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.