Duplicate Row Finder
Find duplicate rows in a CSV, comparing every column or only the columns you choose, such as email. See each group with its line numbers.
Free · No upload · 100% on your device
How to use Duplicate Row Finder
- Type or paste your code or data, or open a file.
- Choose the settings in the side panel. The result updates as you type.
- Copy the result or download it as a file.
Private by design. Everything you type, open or record is processed in this browser tab and is never uploaded to KittySuite.
About Duplicate Row Finder
Line numbers match the file as opened in a text editor or spreadsheet, counting the header as line 1. Choose key columns to find people who signed up twice with different details. Export either the duplicates for review or the unique rows to keep.
Everything runs in this browser tab: your text is never uploaded or stored, and the result updates as you type. It keeps working offline once the page has loaded.
Duplicate Row Finder: frequently asked questions
How do I find duplicate rows in a CSV?
Paste or open the CSV. Each group of duplicates is shown with its line numbers.
Can I find duplicates by one column, such as email?
Yes. Enter key columns so rows match when only those columns are the same.
Do the line numbers match my spreadsheet?
Yes. They match the file as opened in a text editor or spreadsheet, with the header as line 1.
Can I keep only the unique rows?
Yes. Choose to download either the duplicate rows for review or the unique rows to keep.