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COMBINA Function

Excel 2013+

Summary

The COMBINA function calculates the number of combinations with repetition from a given set of items. Unlike standard combinations, COMBINA allows selecting the same item multiple times, making it ideal for scenarios like forming teams where members can be repeated or distributing identical objects into distinct groups.

Syntax

COMBINA(number, number_chosen)

Parameters

Parameter	Type	Required	Description
number	`Number`	Yes	Total number of items available (≥ 0 and ≥ number_chosen). Non-integers are truncated to integers.
number_chosen	`Number`	Yes	Number of items to choose (≥ 0). Non-integers are truncated to integers.

Using the COMBINA Function

COMBINA is perfect for combinatorial problems where order doesn't matter and repetition is allowed. Use it for lottery analysis with replacement, forming committees where the same person can fill multiple roles, or statistical sampling with replacement.

Common COMBINA Examples

Basic Combinations with Repetition

=COMBINA(4,3)

Calculates combinations with repetition for 4 items choosing 3. Result: 20 (allows same item multiple times).

Larger Dataset Example

=COMBINA(10,3)

Number of ways to choose 3 items from 10 with repetition allowed. Result: 220.

Frequently Asked Questions

COMBINA allows repetition (same item can be chosen multiple times), while COMBIN does not permit repetition.

Uses the formula: (N + M - 1)! / (M! × (N - 1)!) where N is number and M is number_chosen.

Common Errors and Solutions

#NUM!

Cause: Number < 0 or number < number_chosen

Solution: Ensure number ≥ 0 and number ≥ number_chosen

#VALUE!

Cause: Non-numeric input provided

Solution: Use only numeric values for both arguments

Notes

Uses mathematical formula for combinations with repetition: C(N+M-1, M)
Non-integer values are automatically truncated
Maximum practical limits apply based on Excel's number precision
Ideal for problems like 'stars and bars' theorem applications

Compatibility

Available in: Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365

Not available in: Excel 2010, Excel 2007, Excel 2003, Earlier versions

Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2013+