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Count unique values

Excel formula: Count unique values
Generic formula 
=COUNTA(UNIQUE(data))
Explanation 

To count unique values in a set of data, you can use the UNIQUE function together with the COUNTA function. In the example shown, the formula in F5 is:

=COUNTA(UNIQUE(B5:B16))

which returns 7, since there are seven unique colors in B5:B16.

How this formula works

This example uses the UNIQUE function to extract unique values. When UNIQUE is provided with the range B5:B16, which contains 12 values, it returns the 7 unique values seen in D5:D11. These are returned directly to the COUNTA function as an array like this:

=COUNTA({"red";"amber";"green";"blue";"purple";"pink";"gray"})

Unlike the COUNT function, which counts only numbers, COUNTA counts both text and numbers. Since there are seven items in array, COUNTA returns 7. This formula is dynamic and will recalculate immediately when source data is changed.

With a cell reference

You can also refer to a list of unique values already extracted to the worksheet with the UNIQUE function using a special kind of cell reference. The formula in D5 is:

=UNIQUE(B5:B16)

which returns the seven values seen in D5:D11. To count these values with a dynamic reference, you can use a formula like this:

=COUNTA(D5#)

The hash character (#) tells Excel to refer to the spill range created by UNIQUE. Like the all-in-one formula above, this formula is dynamic and will adapt when data is added or removed from the original range.

Count unique ignore blanks

To count unique values while ignoring blank cells, you can add the FILTER function like this:

=COUNTA(UNIQUE(FILTER(data,data<>"")))

This approach is explained in more detail here. You can also filter unique values with criteria.

Dynamic source range

UNIQUE won't automatically change the source range if data is added or deleted. To give UNIQUE a dynamic range that will automatically resize as needed, you can use an Excel Table, or create a dynamic named range with a formula. 

Note: This function is a new "Dynamic Array Function" in Excel. It is a beta feature available only through the Office Insiders program. Dynamic Array functions are expected to be released in 2019 to Office 365 subscribers.
Author 
Dave Bruns

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