Permutation & Combination Calculator
Compute nPr and nCr with arbitrary-precision BigInt.
Enter n and r to compute nPr (permutations, order matters) and nCr (combinations, order ignored). Uses BigInt so large factorials don't overflow.
Common use cases
- Count poker hands and lottery combinations
- Solve probability and combinatorics homework
- Estimate the number of password permutations for security analysis
- Compute team selections from a roster
Frequently asked questions
Permutation vs combination?▾
Permutations consider order (ABC ≠ BCA); combinations don't (ABC = BCA). nCr = nPr / r!.
Why BigInt?▾
20! already exceeds JavaScript's safe-integer range. BigInt gives exact results for arbitrarily large n.
Constraints on n and r?▾
Both must be non-negative integers with r ≤ n. The calculator validates this before computing.