To check for duplicates, choose the cells you want to check.
Note that duplicates in the Values section of a PivotTable report cannot be highlighted in Excel.
Duplicate Values can be found by going to Home > Conditional Formatting > Highlight Cells Rules > Duplicate Values.
![Highlight cell rules](https://support.content.office.net/en-us/media/c4363a8a-f25b-444e-8150-236f14c3bbf2.jpg)
Select the formatting you want to apply to the duplicate values in the box next to values with, and then click OK.
![Duplicate Values dialog box](https://support.content.office.net/en-us/media/6c19da52-ccd3-474e-9456-db84f33915d7.jpg)