Fundamental Counting Principle Calculator

The fundamental counting principle calculator will help you find out how many options you have for choosing up to ten characteristics of whatever it is you're dealing with.

Comma separated — e.g. 4 shirts, 3 trousers, 2 pairs of shoes.
Clear
Total combinations244 × 3 × 2
Stages3
If one more stage doubled it48

Running total

StageChoicesRunning total
144
2312
3224

The method

multiply the number of choices at each stage

Why it multiplies

Every choice at one stage can pair with every choice at the next, so the counts multiply rather than add. Four shirts and three trousers give 4 × 3 = 12 outfits, not 7. The growth is exponential in the number of stages, which is why combinatorial totals get large so quickly.