Factorial Calculator
n (non-negative integer, max 1000)
Try a worked example
0! = 1 (by convention)
5! = 120 (common school example)
10! = 3,628,800 (~3.6 million)
13! = 6,227,020,800 (largest that fits in 32-bit signed int)
20! = 2.43 × 10¹⁸ (largest in 64-bit signed int)
52! ≈ 8 × 10⁶⁷ (deck of cards arrangements)