For example, if you have similar data in B2:B11 and C2:C11, and you want to highlight cells where values differ, select the data in both columns, starting from B2, and use this formula: Note: with conditional formatting, it’s important that the formula be entered relative to the “active cell” in the selection, which is assumed to be B2 in this case. The references to $B2 and $C2 are “mixed” - the column is locked, but the row is relative - so only the row number will change as the formula is evaluated. Whenever two values in a row are not equal, the formula returns TRUE and the conditional formatting is applied.

A case-sensitive option

By the “equals to” and “not equals to” operators (= and <>) are not case-sensitive. If you need a case-sensitive comparison, you can use the EXACT function with NOT, like so: Exact performs a case-sensitive comparison and returns TRUE when values match. NOT reverses this logic so that the formula returns TRUE only when the values don’t match.

Another approach

One problem with this approach is that if there is an extra or missing value in one column, or if the data is not sorted, many rows will be highlighted as different. Another approach is to count instances of column A values in column B and highlight values that don’t exist.

Dave Bruns

Hi - I’m Dave Bruns, and I run Exceljet with my wife, Lisa. Our goal is to help you work faster in Excel. We create short videos, and clear examples of formulas, functions, pivot tables, conditional formatting, and charts.