Quick guide
How to use this calculator
- Enter the number of available object types n.
- Enter the selection size r.
- Read the exact number of multisets.
Calculation method
Use the multichoose formula
Choosing r objects from n types with repetition and without order is equivalent to a stars-and-bars arrangement.
Worked example
Choose four scoops from three flavors
Flavors may repeat and scoop order is ignored.
C(3+4−1,4) = C(6,4) = 15
Supported inputs
Precision and limits
Discrete domain
Inputs are whole counts. Negative, fractional, grouped, and scientific-notation inputs are rejected.
Exact integers
Results use arbitrary-precision integers and are never rounded. Inputs and output size are bounded to keep the page responsive.