Quick, clean, and to the point

Highlight duplicate columns

Excel formula: Highlight duplicate columns
Generic formula 

Excel contains a built-in preset for highlighting duplicate values with conditional formatting, but it only works at the cell level. If you want to find and highlight duplicate columns, you'll need to use your own formula, as explained below.

To highlight duplicate columns, you can use a formula based on the SUMPRODUCT function.  In the example shown, the formula used to highlight duplicate columns is:


How this formula works

This approach uses SUMPRODUCT to count the occurrence of every value in the table, one row at a time. Only when the same value appears in the same location in all three rows is a count generated. For cell B4, the formula is solved like this:


Note that row references are fully absolute, while cell references are mixed, with only the row locked.

With a helper row

If you don't mind adding a helper row to your data, you can simplify the conditional formatting formula quite a bit. In a helper row, concatenate all values in the column. Then you can use COUNTIF on that one row to count values that appear more than once, and use the result to trigger conditional formatting in the entire column.

Dave Bruns

Excel Formula Training

Learn Excel formulas and functions with concise, clear videos. Master absolute/relative addresses, dates, text, named ranges, and tools for troubleshooting. Each video comes with a practice worksheet and audio transcript. Instant access and complete 100% guarantee. Start today!

See details.

Your videos are the best one I have seen so far. I use excel in my advanced acc. techniques course and may be coming back to you for some tailored chosen set of videos. - Joanna
Excel foundational video course
Excel Pivot Table video training course
Excel conditional formatting video course
Excel formulas and functions video training course
Excel Shortcuts Video Course