Counting Unique Values

Sometimes you need to know the number of unique values in a range of cells. For instance, suppose that an instructor was teaching the following classes:


In this case there are three unique values. There is no intuitive worksheet function that will return a count of unique values, which makes one think that a user-defined function would be the logical approach. However, you can use an array formula to very easily derive the desired information. Follow these steps:

  1. Define a name that represents the range that contains your list. (This example assumes the name you define is MyRange.)
  2. In the cell where you want the number of unique values to appear type the following formula, but don’t press Enter yet:
  3.      =SUM(1/COUNTIF(MyRange,MyRange))
  4. Instead of pressing Enter, press Ctrl+Shift+Enter. This informs Excel that you are entering an array formula. The formula shown in the formula bar should now appear as follows (notice the addition of the surrounding braces, indicative of array formulas):
  5.      {=SUM(1/COUNTIF(MyRange,MyRange))}

    That’s it! The cell now contains the number of unique name values in the specified range. This approach is not case-sensitive, so if you have two values that differ only in their capitalization (ThisName vs. THISNAME), they are both counted as a single unique value. In addition, there can be no blank cells in the range. (Having a blank cell returns a #DIV/0 error from the formula.)

    If your particular needs require that your list contain blanks (but you don’t want them counted) and you want the evaluation to be case-sensitive, then you must turn to a macro. The following macro, CountUnique, will do the trick:

    Function CountUnique(ByVal MyRange As Range) As Integer
        Dim Cell As Range
        Dim J As Integer
        Dim iNumCells As Integer
        Dim iUVals As Integer
        Dim sUCells() As String
        iNumCells = MyRange.Count
        ReDim sUCells(iNumCells) As String
        iUVals = 0
        For Each Cell In MyRange
            If Cell.Text > "" Then
                For J = 1 To iUVals
                    If sUCells(J) = Cell.Text Then
                        Exit For
                    End If
                Next J
                If J > iUVals Then
                    iUVals = iUVals + 1
                    sUCells(iUVals) = Cell.Text
                End If
            End If
        Next Cell
        CountUnique = iUVals
    End Function

    Simply put an equation similar to the following in a cell:


    The value returned is the number of unique values, not counting blanks, in the range. Understand, as well, that as your range (what you defined as MyRange, earlier) becomes larger, the macro takes longer to process. This is understandable; it has to work through all the cells in the range, and if there are a lot of cells it can take a lot of time.