How to find the duplicate values in your Excel columns? It's very easy with a single formula.
Combination of FILTER and COUNTIF functions
To find the duplicate values, we need to associate the FILTER and COUNTIF functions.
- The COUNTIF function
We will create a logical test with this function to find duplicate values
- The FILTER function
This function will be used to keep only the duplicate values
In our example, the data have been added to a Table (Insert > Table), and the table name is tbl_Data. This information will be used in the references of the formula.
Create the test to find the duplicate values
Since the dynamic array functions have been added to Excel, you can write the standard Excel functions differently. For instance, with COUNTIF, you can write a range of cells as criteria, and not only for one cell like it us to be.
=COUNTIF(tbl_Data[Value],tbl_Data[Value])
And then, we simply convert this function into a logical test for all the values greater than 1
=COUNTIF(tbl_Data[Value],tbl_Data[Value])>1
Keep only the duplicate values
To keep only duplicate values, we will insert the previous logical test as a criterion for the function FILTER. The beauty of FILTER is to return the values when the test is TRUE.
=FILTER(tbl_Data[Value],COUNTIF(tbl_Data[Value],tbl_Data[Value])>1)
Of course, it's not necessary to return every duplicate value. So you can embed the previous formula into the UNIQUE function.
=UNIQUE(FILTER(tbl_Data[Value],COUNTIF(tbl_Data[Value],tbl_Data[Value])>1))
