Combination Calculator (nCr)
Calculate the number of combinations of n items taken r at a time (nCr).
How to use this tool
- Enter n (total items) and r (items chosen) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your ncr and the full breakdown beneath it.
nCr = n! / (r! × (n−r)!) counts unordered selections of r items from n.
Frequently asked questions
- What is a combination?
- A combination is an unordered selection. nCr = n!/(r!(n-r)!). For example, C(5,2) = 10 — choosing 2 from 5 ignoring order.