Select your range
Choose one continuous block—a column, a table, or a whole-column selection. Refresh the sidebar after changing the selection.
Sheet1!A2:D500
How it works
Select. Highlight. Get back to work.
Duplicate Highlighter for Google Sheets lives in the Extensions menu of the spreadsheet you have open. Use the sidebar for precise matching or Quick Apply for your last-used settings.
Define a duplicate
Compare values per column, across the whole range, or match complete rows using selected key columns.
Blanks ignoredSpaces trimmedCase optional
Apply—and leave it
Preview the current matches, then apply a native conditional-formatting rule. It keeps working after the sidebar and spreadsheet close.
✓ Native rule applied
The next time, skip the sidebar
Highlight Selected Range runs your saved matching preferences directly from the Extensions menu.
Clear all highlights on active sheet removes every rule Duplicate Highlighter owns on the current sheet; the sidebar's Clear this selection is limited to your selected range. Undo last highlight reverses the most recent apply while its ownership checks still match.
What it can see
The spreadsheet currently open, under Google's currentonly permission. It does not browse your Drive.
What Codeprint keeps
Your account, installation, successful-use count, and subscription status—not spreadsheet contents or duplicate values.
Who made it
Codeprint. Duplicate Highlighter is an independent add-on and is not a Google product.
Ready to clean up the visual noise?
Try every matching option with three successful applies free.