Factorial Calculator
Calculate factorials, permutations, and combinations for any number with step-by-step computation
5!
120
3 digits
Step by Step
5! = 5 × 4 × 3 × 2 × 1 = 120
n! = n × (n-1) × (n-2) × ... × 1
P(n,r) = n! / (n-r)! — ordered arrangements
C(n,r) = n! / (r! × (n-r)!) — unordered selections
How to Use This Tool
Choose a mode: Factorial (n!), Permutation P(n,r), or Combination C(n,r).
Enter the value of n (and r for permutations/combinations).
View the result with full BigInt precision — no rounding, even for huge numbers.
For small factorials, see the step-by-step expansion.
About This Tool
Factorial Calculator computes factorials, permutations, and combinations with BigInt support for arbitrarily large results. See the step-by-step expansion for factorials up to 20. Permutations P(n,r) count ordered arrangements, while Combinations C(n,r) count unordered selections. Can compute even 1000! with full precision.
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