TFT

Calculate Factorials (n!) Online

Compute the factorial of any number instantly. Also calculate permutations, combinations, double factorials, and subfactorials for math and statistics.

Number Factorial Calculator

Calculate factorial, double factorial, permutations, and combinations

Formulas

n! = n × (n-1) × ... × 1
5! = 5 × 4 × 3 × 2 × 1 = 120
n!! = n × (n-2) × (n-4) × ...
5!! = 5 × 3 × 1 = 15
P(n,r) = n! / (n-r)!
P(5,3) = 5! / 2! = 60
C(n,r) = n! / (r! × (n-r)!)
C(5,3) = 5! / (3! × 2!) = 10