Combinations Calculator
🎲 Statistics & probability. Use the Combinations (n choose r) formula to find combinations, n, r: pick the value you want, type the others, and the answer updates as you go.
Combinations120
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Combinations | no unit |
| n | no unit |
| r | no unit |
Worked example
Find the combinations when n = 10, r = 3.
Using ⁿCr = n!/(r! (n - r)!): Combinations = 120.
Frequently asked questions
What is the formula for Combinations (n choose r)?
ⁿCr = n!/(r! (n - r)!).
What do the letters stand for, and what units are used?
Combinations, n, r.
How do you calculate combinations?
Put the values into ⁿCr = n!/(r! (n - r)!). For example, with n = 10, r = 3, combinations = 120.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (combinations, n, r) and fill in the others: it rearranges the formula for you.
