Combination Calculator: The Complete Guide
Count the unordered selections of items. Enter the total number of items (n) and how many you choose (r) to get nCr — the number of combinations where order doesn't matter.
Who the Combination Calculator is for
Students and analysts counting unordered selections for probability and combinatorics.
How to use the Combination Calculator
- Type your values into the fields above — pick your currency or units where the calculator offers them.
- Results update automatically as you type; there's no submit button and nothing is sent to a server.
- Adjust any input to compare scenarios, then copy the result with a single click.
How it works
nCr = n! ÷ (r! × (n − r)!) — the number of ways to choose r items from n when the order of selection doesn't matter.
Features
- nCr combinations
- Shows the notation
- Permutations for comparison
- Instant result
When order doesn't matter
A combination counts selections where order is irrelevant — like choosing a committee or lottery numbers. Because A-B-C is the same selection as C-B-A, nCr is smaller than the matching permutations count. Combinations are central to probability, lotteries, and binomial math.