How to compare data in two columns to find duplicates in Excel

You can use the following methods to compare data in two Microsoft Excel worksheet columns and find duplicate entries. 

Method 1: Use a worksheet formula

  1. Start Excel.

  2. In a new worksheet, enter the following data as an example (leave column B empty):

    A

    B

    C

    1

    1

    3

    2

    2

    5

    3

    3

    8

    4

    4

    2

    5

    5

    0

  3. Type the following formula in cell B1:

    =IF(ISERROR(MATCH(A1,$C$1:$C$5,0)),"",A1)

  4. Select cell B1 to B5.

  5. In Excel 2007 and later versions of Excel, select Fill in the Editing group, and then select Down.

    The duplicate numbers are displayed in column B, as in the following example: 

    A

    B

    C

    1

    1

    3

    2

    2

    2

    5

    3

    3

    3

    8

    4

    4

    2

    5

    5

    5

    0

Method 2: Use a Visual Basic macro

Warning: Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure. However, they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements.

To use a Visual Basic macro to compare the data in two columns, use the steps in the following example:

  1. Start Excel.

  2. Press ALT+F11 to start the Visual Basic editor.

  3. On the Insert menu, select Module.

  4. Enter the following code in a module sheet:

    Sub Find_Matches()
    Dim CompareRange As Variant, x As Variant, y As Variant
    ' Set CompareRange equal to the range to which you will
    ' compare the selection.
    Set CompareRange = Range("C1:C5")
    ' NOTE: If the compare range is located on another workbook
    ' or worksheet, use the following syntax.
    ' Set CompareRange = Workbooks("Book2"). _
    ' Worksheets("Sheet2").Range("C1:C5")
    '
    ' Loop through each cell in the selection and compare it to
    ' each cell in CompareRange.
    For Each x In Selection
    For Each y In CompareRange
    If x = y Then x.Offset(0, 1) = x
    Next y
    Next x
    End Sub
  5. Press ALT+F11 to return to Excel.

    1. Enter the following data as an example (leave column B empty):
       

      A

      B

      C

      1

      1

      3

      2

      2

      5

      3

      3

      8

      4

      4

      2

      5

      5

      0

  6. Select cell A1 to A5.

  7. In Excel 2007 and later versions of Excel, select the Developer tab, and then select Macros in the Code group.

    Note: If you don't see the Developer tab, you may have to turn it on. To do this, select File > Options > Customize Ribbon, and then select the Developer tab in the customization box on the right-side.

  8. Click Find_Matches, and then click Run.

    The duplicate numbers are displayed in column B. The matching numbers will be put next to the first column, as illustrated here:

    A

    B

    C

    1

    1

    3

    2

    2

    2

    5

    3

    3

    3

    8

    4

    4

    2

    5

    5

    5

    0

Expand your Office skills
Explore training
Get new features first
Join Office Insiders

Was this information helpful?

Thank you for your feedback!

Thank you for your feedback! It sounds like it might be helpful to connect you to one of our Office support agents.

×