Combination Calculator
Calculate combinations nCr (order does not matter).
Formula: nCr = n! / (r!(n−r)!)
Worth Knowing
Combinations count how many ways you can choose r items from n when order doesn't matter — the lottery is the classic example, since drawing 1-2-3 is the same ticket as 3-2-1. The formula divides the permutation count by r! precisely to remove those reorderings. Combinations grow explosively: choosing 6 from 49 already gives nearly 14 million possibilities, which is exactly why big lottery jackpots are so hard to win.
How to Use
- Enter n (total items) into the first field of the Combination Calculator.
- Fill in the rest: r (chosen).
- Your result appears instantly as you type — there's no submit button or page reload.
Formula
nCr = n! / (r!(n−r)!)