Logik: Highlight Duplicates is a simple Google Sheets™ add-on that scans your current sheet and automatically highlights duplicate entries. It’s designed for things like giveaway sign-ups, mailing lists, class rosters, or any spreadsheet where each person should only appear once.

With one click, the add-on applies conditional formatting to mark duplicates in real time, so late submissions or new rows are caught automatically. All processing happens inside your document—no data is exported or stored on external servers.

Use the links below for our Terms of Service, Privacy Policy, and Support information for this add-on.