Please Note: This article is written for users of the following Microsoft Excel versions: 2007, 2010, 2013, 2016, 2019, and Excel in Office 365. If you are using an earlier version (Excel 2003 or earlier), this tip may not work for you. For a version of this tip written specifically for earlier versions of Excel, click here: Deleting Duplicate Columns.

# Deleting Duplicate Columns

by Allen Wyatt
(last updated October 20, 2018)

Dror has a worksheet that contains quite a bit of data. It is possible that the data in one column will be exactly the same as the data in another column, so he wonders if there is an easy way to delete any duplicate columns within the worksheet.

The first step, of course, is to figure out if two columns are identical or not. This can be determined rather easily with an array formula such as the following:

```=AND(A1:A100=B1:B100)
```

(Remember that an array formula is entered by using Shift+Ctrl+Enter.) The formula compares all the values in the first 100 rows of columns A and B. If they are all the same, then the formula returns TRUE. If any of the cells don't match, then the formula returns FALSE. If the result is TRUE you could then delete one of the columns because they are the same.

If you want something that is a bit more automatic, meaning that the duplicate column is deleted, then you'll need to use a macro. The following steps through all the columns in the worksheet and, starting with the right-most column, compares all the columns. If any are the same—regardless of their order in the worksheet—then the macro asks if you want the duplicate column deleted.

```Sub DeleteDuplicateColumns()
Dim rngData As Range
Dim arr1, arr2
Dim i As Integer, j As Integer, n As Integer

On Error Resume Next
Set rngData = ActiveSheet.UsedRange
If rngData Is Nothing Then Exit Sub

n = rngData.Columns.Count

For i = n To 2 Step -1
For j = i - 1 To 1 Step -1
If WorksheetFunction.CountA(rngData.Columns(i)) <> 0 And _
WorksheetFunction.CountA(rngData.Columns(j)) <> 0 Then
arr1 = rngData.Columns(i)
arr2 = rngData.Columns(j)
If AreEqualArr(arr1, arr2) Then
With rngData.Columns(j)
'mark column to be deleted
.Copy
If MsgBox("Delete marked column?", vbYesNo) _
= vbYes Then
rngData.Columns(j).Delete
Else
'remove mark
Application.CutCopyMode = False
End If
End With
End If
End If
Next j
Next i

End Sub
```
```Function AreEqualArr(arr1, arr2) As Boolean
Dim i As Long, n As Long
AreEqualArr = False
For n = LBound(arr1) To UBound(arr1)
If arr1(n, 1) <> arr2(n, 1) Then
Exit Function
End If
Next n
AreEqualArr = True
End Function
```

Note:

If you would like to know how to use the macros described on this page (or on any other page on the ExcelTips sites), I've prepared a special page that includes helpful information. Click here to open that special page in a new browser tab.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (5674) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, and Excel in Office 365. You can find a version of this tip for the older menu interface of Excel here: Deleting Duplicate Columns.

##### Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He is president of Sharon Parq Associates, a computer and publishing services company. ...

##### MORE FROM ALLEN

Allowing Sentence Fragments

Grammar, particularly in English, has a perplexing array of rules and exceptions to those rules. Word does a fairly good ...

Discover More

Searching for Text Not Using a Certain Style

Word is very flexible in what it allows you to search for. One thing it can't do, however, is allow you to search for ...

Discover More

Using the Same Range Name on Different Worksheets

Defined names can be a great boon when working in a worksheet. Usually names are available throughout an entire workbook, ...

Discover More

Create Custom Apps with VBA! Discover how to extend the capabilities of Office 2013 (Word, Excel, PowerPoint, Outlook, and Access) with VBA programming, using it for writing macros, automating Office applications, and creating custom applications. Check out Mastering VBA for Office 2013 today!

##### More ExcelTips (ribbon)

Forcing Input to Uppercase

If you type information into a workbook, you may want to make sure that what you type is always stored in uppercase. ...

Discover More

Pasting Excel Data within Word's Page Margins

The programs in the Microsoft Office suite are designed to work with each other easily. Sometimes there can be hiccups ...

Discover More

Pasting without Updating References

Do you need to paste formulas without updating the references in whatever you are pasting? You can accomplish this, ...

Discover More
##### Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

If you would like to add an image to your comment (not an avatar, but an image to help in making the point of your comment), include the characters [{fig}] in your comment text. You’ll be prompted to upload your image when you submit the comment. Maximum image size is 6Mpixels. Images larger than 600px wide or 1000px tall will be reduced. Up to three images may be included in a comment. All images are subject to review. Commenting privileges may be curtailed if inappropriate images are posted.

What is 9 + 9?

2018-10-22 11:01:49

Roy

@Bill

When you enter a formula, you ordinarily finish it off by pressing the Enter key, or even by clicking a cell with the mouse.

For an array formula you finish it off differently: you press the key combination Shift-Control-Enter.

If you do not, Excel does not treat it as an array formula and you will get a wrong result or perhaps an error. (It's possible to get a correct result, but only if: a) by chance, or b) due to Excel's "relative" handling of some functions. Also, the "by chance" possibility is usually only for the first cell with the array formula. If you put it in 10 cells, the other nine are probably wrong. And the second possibility only works in the rows looked at (for instance, if you have ten cells in rows 1-10 that you look at, but your array formula is in rows 4-13, only rows 4-10 might have correct results while rows 11-13 will give you an error, no matter what). And often a function is arranged differently or has dfferent options ("arguments") as an array formula than when it is not, so you can't even have chance work for you.

Since many formulas can work as array formulas, or not, you may not get an error and wonder what you did wrong: it looks perfectly all right so long as the result is not obviously impossible if it worked right (like you expect a result over 200,000 but the result you get is 43) and you go merrily on thnking you're golden though you're nothing of the kind.

Lastly, given the comment, I would also point out that looking at an array formula, you will see it looks different as well. It will have a curly brace ("{") BEFORE the "=" and another one ("}") after everything else"

=B1 NOT being treated by Excel as an array formula
{=B1} IS being treated by Excel as an array formula

2018-10-22 10:46:53

Dave Bonin

Bill,

If you are not familiar with array formulas, then I recommend you don't use them. They are easy to accidentally break, especially if your workbook is used by others who are also not familiar with array formulas.

Here's a regular formula that will work just as well:
= SUMPRODUCT( - - ( A1:A100 = B1:B100 )) = ROW( A100 ) - ROW( A1 ) + 1

Adjust the row numbers as needed. For example, if your data starts in row 5 and contains 512 values:
= SUMPRODUCT( - - ( A5:A516 = B5:B516 )) = ROW( A516 ) - ROW( A5 ) + 1

Of course, if your data starts in row 5, and it currently contains 512 values, and you add more from time-to-time, and there's nothing else below your data, then this will work too and you won't have to adjust it.
= SUMPRODUCT( - - ( A5:A1000 = B5:B1000 )) = ROW( A1000 ) - ROW( A5 ) + 1

Knowing the pedantic nature of some readers of these tips, keep watching for more elegant solutions.

2018-10-22 06:15:01

Bill

What do you mean, “Remember that an array formula is entered by using Shift=Ctrl+Enter.”? I don’t have a clue what you are referring to. I certainly could use this tip, so I appreciate any clarification.

2018-10-22 03:20:04

Thomas Papavasileiou

Elegant solution
Just a remark. The need of "On Error Resume Next" command is obvious, but as a best practice I think that it should be followed by "On Error GoTo 0"
as soon as possible and in this preseny case just before the "n = rngData.Columns.Count" line.
That will contribute to easily debug any programming or mismatch error that may occur in the remaning part of the macro.

2018-10-21 06:51:03

Willy Vanhaelen

The macro can be shorter by using the array formula mentioned in this tip instead of the AreEqualArr function.
This formula can be implemented in vba by usingf the Evaluate method:

& "=" & RngData.Columns(j).Address & ")") Then

replaces

arr1 = rngData.Columns(i)
arr2 = rngData.Columns(j)
If AreEqualArr(arr1, arr2) Then

so we don't need the AreEqualArr function anymore:

Sub DeleteDuplicateColumns()
Dim rngData As Range
Dim i As Integer, j As Integer

On Error Resume Next
Set rngData = ActiveSheet.UsedRange
If rngData Is Nothing Then Exit Sub

For i = rngData.Columns.Count To 2 Step -1
For j = i - 1 To 1 Step -1
If Application.CountA(rngData.Columns(i)) <> 0 And _
Application.CountA(rngData.Columns(j)) <> 0 Then
If Evaluate("AND(" & rngData.Columns(i).Address & _
"=" & rngData.Columns(j).Address & ")") Then
With rngData.Columns(j)
.Copy 'mark column to be deleted
If MsgBox("Delete marked column?", vbYesNo) _
= vbYes Then
rngData.Columns(j).Delete
Else 'remove mark
Application.CutCopyMode = False
End If
End With
End If
End If
Next j
Next i

##### This Site

Got a version of Excel that uses the ribbon interface (Excel 2007 or later)? This site is for you! If you use an earlier version of Excel, visit our ExcelTips site focusing on the menu interface.

##### Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."