Combinatorics Calculator
Calculate permutations (nPr) and combinations (nCr) instantly.
📐 Formulas
nPr = n! / (n-r)!
Order matters
nCr = n! / (r! × (n-r)!)
Order doesn't matter
n! = n × (n-1) × ... × 1
Factorial
🔢 Results will appear here
Enter n and r values, then click "Calculate"
Combinatorics Calculator
Calculate permutations and combinations for probability and counting problems. Our calculator handles both ordered (permutations) and unordered (combinations) selections.
Essential for probability theory, statistics, and discrete mathematics.