This combinations and permutations calculator works out nCr (combinations) and nPr (permutations) of n items taken r at a time, with exact results.
How many ways are there?
Combinatorics answers “in how many ways can I…?” — useful for probability, statistics, lottery odds and maths problems in general. Enter n (total items) and r (how many you choose) to get both values instantly, computed with arbitrary-precision arithmetic so even huge results stay exact.