COMBIN

The number of ways to choose a number of items from a set, order not counting.

Group: Math. Compatible with DAX.

Syntax

COMBIN ( <number>, <number_chosen> )

Parameter	Type	Description
`number`	Whole number	How many items there are to choose from.
`number_chosen`	Whole number	How many of them are chosen.

Number. How many different groups of that size can be picked, the order inside a group not counting.

From five beers, COMBIN ( 5, 2 ) gives the 10 different pairs.
Both numbers are rounded to whole numbers first, a half away from zero: 5.5 counts as 6, so COMBIN ( 5.5, 2 ) gives 15.
Choosing none or all gives 1. A negative number, or choosing more items than there are, is an error.
When the order counts, use PERMUT; when an item may be picked more than once, COMBINA.

EVALUATE
ROW (
    "Pairs of 5", COMBIN ( 5, 2 ),
    "Hands of 5 from 52", COMBIN ( 52, 5 ),
    "Of 5.5, 2", COMBIN ( 5.5, 2 )
)

Pairs of 5	Hands of 5 from 52	Of 5.5, 2
10	2598960	15

EVALUATE
ROW (
    "COMBIN", COMBIN ( 10, 3 ),
    "PERMUT", PERMUT ( 10, 3 ),
    "COMBINA", COMBINA ( 10, 3 )
)

COMBIN	PERMUT	COMBINA
120	720	220

Last updated 3 November 2026 · OpenBI Studio 0.3.74