Returns the number of combinations for a given number of items. Use COMBIN to determine the total possible number of groups for a given number of items.
Syntax
COMBIN(number,number_chosen)
Number is the number of items.
Number_chosen is the number of items in each combination.
Remarks
 Numeric arguments are truncated to integers.
 If either argument is nonnumeric, COMBIN returns the #VALUE! error value.
 If number < 0, number_chosen < 0, or number < number_chosen, COMBIN returns the #NUM! error value.
 A combination is any set or subset of items, regardless of their internal order. Combinations are distinct from permutations, for which the internal order is significant.
 The number of combinations is as follows, where number = n and number_chosen = k:
where:
Example
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example
 Create a blank workbook or worksheet.
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Note Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 In the worksheet, select cell A1, and press CTRL+V.
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A 
B 
Formula 
Description (Result) 
=COMBIN(8,2) 
Possible twoperson teams that can be formed from 8 candidates (28) 
