COMBINA Function

Excel Functions › Math & Trig

Excel 2013+ Math & Trig

The Excel COMBINA function returns the number of combinations with repetition — how many ways you can choose items from a set when order does not matter but the same item may be picked more than once.


Quick answer:
=COMBINA(4,3) = 20

Syntax

=COMBINA(number, number_chosen)
ArgumentDescription
numberRequiredThe total number of distinct items to choose from (n).
number_chosenRequiredHow many items are chosen (k). With repetition allowed, k may exceed n.

How to use it

COMBINA is like COMBIN but allows the same item to be chosen repeatedly. Picking 3 scoops from 4 ice-cream flavors (you can repeat a flavor) is =COMBINA(4,3) = 20.

=COMBINA(4,3) // repetition allowed = 20
=COMBINA(3,2) // = 6
=COMBINA(5,3) // = 35

Mathematically COMBINA(n,k) = COMBIN(n + k - 1, k). Because repeats are allowed, the count is always at least as large as the equivalent COMBIN, and k is even permitted to exceed n.

COMBIN vs COMBINA: COMBIN forbids repeats (each item picked at most once); COMBINA allows them. For 3 scoops from 4 flavors, COMBINA(4,3) = 20 because you can take two or three scoops of the same flavor.

Try it: interactive demo

Live demo

Pick a COMBINA example to see the formula and its result.

Result:

Practice workbook

📊
Download the free COMBINA practice workbook
Every example on this page, ready to open in Excel — plus practice challenges with answers on a separate tab. No sign-up required.

Frequently asked questions

What does COMBINA calculate?
Combinations with repetition: the number of ways to choose k items from n when order doesn't matter but items may repeat. =COMBINA(4,3) = 20.
How is COMBINA different from COMBIN?
COMBIN forbids repeats (each item used at most once); COMBINA allows the same item to be chosen multiple times, so its counts are larger.
Can number_chosen be larger than number?
Yes — because repetition is allowed, you can choose more items than there are distinct options. That would be invalid for COMBIN but is fine for COMBINA.
Is there a formula linking COMBINA to COMBIN?
Yes: COMBINA(n,k) = COMBIN(n + k - 1, k). The two are directly related through this shift.

Master functions like this in one day

This page covers one function. Our Excel Formulas and Functions class covers the 30 that matter most — live, hands-on, taught by professionals in Dallas–Fort Worth, Houston, Austin, Oklahoma City, Denver, or online.

See the Formulas & Functions Class

Related functions: COMBIN · FACT · FACTDOUBLE · MULTINOMIAL · GCD