It stays live
The add-on creates a native conditional-formatting rule. Paste new data and duplicates color themselves; fix one and the color disappears.
Google Workspace Marketplace listing in progress
Duplicate Highlighter for Google Sheets finds repeats in one click.
Select a range, choose how duplicates should match, and apply real conditional formatting—no formulas, scripts, or COUNTIF setup to maintain.
First 3 successful highlights are free. Then $29.99 a year for unlimited applies.
Four duplicate emails highlighted—and the rule stays live.
Why use Duplicate Highlighter
Values or whole rows
Compare each column, compare the entire range, or match rows on key columns such as email and phone.
Nothing gets deleted
It colors cells without rewriting values or formulas. Clear removes only rules owned by Duplicate Highlighter.
The matching options
“Anna ” and “anna” may be the same person. Your spreadsheet disagrees.
Trailing spaces, stray capitals, and empty cells are why common duplicate tricks miss matches. Plain-language switches handle them without exposing a formula.
Ignore blank cells
Trim spaces before matching
Treat ANNA and anna as the same
Leave the first of each set alone
Pricing
One price. No seats, credits, or surprise overages.
Three successful applies are free so you can test the add-on on your own data. Pro is $29.99 a year for unlimited applies on your Google account.
What counts as a use?Free trial
3successful applies
- Every feature unlocked
- Unlimited previews
- No payment card required
- Clear and Undo stay free
Pro
$29.99/ year
- Unlimited successful applies
- Every spreadsheet you use
- All matching modes and colors
- Cancel any time
Questions
Frequently asked questions
How do I highlight duplicates in Google Sheets?
Install Duplicate Highlighter, select one continuous range, open the add-on, choose how duplicates should match, and apply. It creates a native conditional-formatting rule that keeps updating.
Does the highlighting stay after I close the add-on?
Yes. The result is a native Google Sheets conditional-formatting rule, so it remains in the spreadsheet and continues updating after the sidebar closes.
Does Duplicate Highlighter delete or change my data?
No. It adds or removes conditional-formatting rules owned by the add-on. Cell values, formulas, row order, and unrelated formatting are not rewritten or deleted.
Can it find duplicate rows instead of duplicate cells?
Yes. Choose the key columns that define a duplicate row, such as email and phone, while excluding columns such as notes.
What counts as one of the three free uses?
Only a highlight rule that is successfully applied, including Quick Apply. Opening the sidebar, previewing, changing settings, clearing rules, errors, and canceled operations do not count.
Will Clear remove my other conditional formatting?
No. Clear is designed to remove only rules created and owned by Duplicate Highlighter. Other conditional-formatting rules remain in place.
Can it ignore blanks, spaces, or capitalization?
Yes. You can ignore blank cells, trim surrounding whitespace, and choose whether uppercase and lowercase values should match.
Does it work on the Google Sheets mobile app?
Google does not support add-on sidebars on mobile. Rules applied from desktop continue to display and update in Sheets on supported devices.
Does spreadsheet data leave Google Sheets?
No. Duplicate detection and rule generation run in the Google Apps Script session. Codeprint receives identity, installation, usage, and subscription records—not cell values, formulas, sheet names, ranges, or duplicate groups.
Find the duplicates you already suspect are in there.
The first three successful highlights are free. No payment card required.