Factorial Calculator
Calculate n! (n factorial) — the product of all whole numbers from 1 to n — with exact, full-precision results.
Input
Result:
Digits:
What is a factorial?
n! = n × (n − 1) × (n − 2) × … × 2 × 1, and 0! is defined as 1. Factorials grow extremely fast — 20! already exceeds 2 quintillion, and this calculator uses arbitrary-precision arithmetic to keep every digit exact up to n = 1000.