Permutation & Combination Calculator

Permutation & Combination – Quick Cheat Sheet

• Combinations (nCr): order doesn’t matter.
  nCr = n! / (r!(n−r)!)
• Permutations (nPr): order matters.
  nPr = n! / (n−r)!
• Constraints: integers with 0 ≤ r ≤ n.
• Scaling: values grow very quickly; the tool shows digit count and a scientific form when the exact number is huge.
• Tip: Use combinations for “teams/sets”; permutations for “arrangements/orders”.