How it works
Count selections without replacement when order does not matter. The selected count cannot exceed available items.
C(n,k) = n! / [k!(n−k)!]
Worked example
Show example inputs and result
Available items: 10 · Items selected: 3.
- Result
- 120
Questions and answers
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method reviewed: October 8, 2026 · Methods & accuracy