Combination vs permutation: the practical difference.
The simplest test is this: if changing the order creates a different result, use a permutation. If order does not matter, use a combination.
Combination
Order does not matter
Choosing A and B is the same selection as choosing B and A.
AB, AC, BCPermutation
Order matters
AB and BA are different because the sequence changes.
AB, BA, AC, CA, BC, CBQuick decision rule
- Use combinations for teams, selections, groups, pairs, and unordered sets.
- Use permutations for rankings, passwords, codes, ordered schedules, and sequences.
- Use repetition only when the same item can appear more than once inside one result.
Examples
Team of two from Alice, Ben, and Cara
Use a combination. Alice + Ben is the same team as Ben + Alice.
Two-character code from A, B, and C
Use a permutation if AB and BA should count as different codes.
Try both modes
ComboKit Studio includes both a generator and exact count calculators, so you can compare the output size before creating rows.