Permutation and Combination Calculator
Calculate permutations and combinations to solve counting problems in mathematics, probability, and statistics. It is useful for study, lab preparation, engineering notes, or checking a calculation where consistent units matter.
How to use this calculator
Enter whole-number values within the range supported by the calculator. Check whether the problem is about order (permutations) or selection without order (combinations) before choosing the calculation.
Formula
nPr = n! Γ· (nβr)! and nCr = n! Γ· [r!(nβr)!].
Quick check
Check the result against a rough estimate. A quick mental check can reveal a misplaced decimal or an incorrect unit. For technical or academic work, write down the units alongside the numbers. A mathematically correct calculation can still be misleading if the units are wrong.