Excel Formula to find conditional duplicate instances in a column

[mchilapur]

Hello Excel Experts,

I am trying to find the total number of duplicate instances based on user Input.
In the attached sample data, i have data in column A,B, C spread across 40K rows (even more). So based on category (1 input) and sub category (2 inputs), i want to find the duplicate instances of 'Item Number'. In the attached example, category is 2000, and sub category is A and D, so there is one 'Item Number' duplicated which is "AB1236", hence count will be 1.

Can anyone please help me with the excel formulas to pull the total duplicate counts.? All are Random values in column A,B,C and nothing is standardized.

Thanks for the help.

[Glenn Kennedy]

Edit: wrong formula. reply withdrawn

[JohnTopley]

First a better example file would help as all the Item Numbers are repeated.

And if understand your request, you need to identify all multiple occurrences of a given Item Number and then list the associated categories/sub categories for each replicated item number.

How many sub-categories are there ?

[mchilapur]

Hi John..
All i am trying to indentify is how many "item numbers" are common in a given Category and then within the 2 sub-categories...
I have very huge data, around 80K rows and unique sub-categories may be around 2K and also these values change between each reports.

[mchilapur]

Edit: wrong formula. reply withdrawn

Hi Glenn, your formula is almost through, only thing is you did not consider 2nd sub category into consideration. Can you please help..?