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

More information regarding comparison of data in two columns is available at, however method 1 in this solution is an interesting approach to this issue.

Method 1: Use a worksheet formula
To use a worksheet formula to compare the data in two columns, follow these steps:

  1. 1. Start Excel
  2. In a new worksheet, enter the following data (leave column B empty):
    A1: 1   B1:     C1: 3
    A2: 2   B2:     C2: 5
    A3: 3   B3:     C3: 8
    A4: 4   B4:     C4: 2
    A5: 5   B5:     C5: 0
  3. Type the following formula in cell B1:
  4. Select cells B1:B5.
  5. In Microsoft Office Excel 2003 and in earlier versions of Excel, point to Fill on the Edit menu, and then click Down.

In Microsoft Office Excel 2007, click Fill in the Editing group, and then click Down.

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

A1: 1   B1:     C1: 3
A2: 2   B2: 2   C2: 5
A3: 3   B3: 3   C3: 8
A4: 4   B4:     C4: 2
A5: 5   B5: 5   C5: 0