Calculate factorials, permutations, and combinations with this free factorial calculator. Great for algebra, probability, statistics, and counting problems.
Factorial:
n! = n × (n - 1) × (n - 2) × ... × 1
Permutation:
P(n,r) = n! / (n-r)!
Combination:
C(n,r) = n! / (r!(n-r)!)
These formulas are widely used in algebra, counting, probability, and statistics.
Factorials help count the number of possible arrangements and selections. They are essential in permutations, combinations, binomial formulas, and probability.
They are especially useful when solving counting problems with many possible outcomes.
Your result shows the factorial, permutation, or combination value based on the selected mode. Supporting values help explain the expression used and how the answer was built.
This makes it easier to verify counting and probability work for school, statistics, or real-world arrangement problems.
0! equals 1 by definition.
Permutations care about order, while combinations do not.
Each factorial multiplies by every whole number down to 1, so the result grows very fast.
Not in this calculator. It works with non-negative whole numbers only.