COMBINA Function

The COMBINA function returns the number of combinations for a given number of items. A combination is a group of items where order does not matter.  There are two kinds of combinations:

1. Combinations that do not allow repetitions (e.g. 123)
2. Combinations that do allow repetitions (e.g. 333)

The COMBINA function allows repetitions. To count combinations that do not allow repetitions, use the COMBIN function. To count permutations (combinations where order does matter) see the PERMUT function.

The COMBINA function takes two arguments: number, and number_chosen. Number is the number of different items available to choose from. The number_chosen argument is the number of items in each combination. Both arguments are required.

Example

To use COMBINA, specify the total number of items and "number_chosen", which represents the number of items in each combination. For example, to calculate total 3-number combinations of numbers between 0-9, you can use a formula like this:

=COMBINA(10,3) // returns 220

The number argument is 10 since there are ten numbers between 0 and 9 available. Number_chosen is 3, since there are three numbers for each combination.

In the example shown above, the formula in cell D6, copied down, is:

=COMBINA(B6,C6)

At each new row, COMBINA calculates returns the number of combinations using the values in column B for number, and the values in column C for number_chosen. The results can be seen in column D.

Notes

• A combination is a group of items in any order. If order matters, use the PERMUT function.
• Arguments that contain decimal values are truncated to integers.
• COMBINA returns a #VALUE! error value if either argument is not numeric.