CSV Deduplicator
Remove duplicate rows from CSV or TSV data — dedupe on all columns or a key column, keeping the first or last match.
Drag & drop a .csv or .tsv file here, or click to browse
No uploads. Your files stay on your device.
How it works
Paste your CSV — or drop a .csv/.tsv file — and duplicate rows are
removed instantly. Parsing follows RFC 4180, so quoted fields containing commas, line breaks
and escaped "" quotes are compared correctly, and the delimiter (comma,
semicolon, tab or pipe) is auto-detected. By default a row counts as a duplicate only when
every column matches, but you can switch to “Selected columns only” and dedupe on a key such
as an email address or order ID. Choose whether the first or the last occurrence survives,
and turn off case sensitivity to treat Alice and alice as the same
person.
The header row is never treated as data, the original row order is preserved, and every row that was dropped is listed separately so you can check the result before you commit to it. Everything runs in your browser with JavaScript — the CSV is never uploaded, stored or logged, which makes this safe for customer exports and mailing lists.
Frequently asked questions
How do I remove duplicate rows from a CSV file?
Paste your CSV into the box or drop a .csv/.tsv file on the page — duplicate rows disappear instantly. By default a row is a duplicate only when every column matches, the header row is left alone and the original row order is preserved. Use Copy CSV or Download .csv to save the cleaned file.
Can I deduplicate on one column, like an email address?
Yes. Switch “Compare” to “Selected columns only” and pick the key columns — for example just the email or order ID — and rows are merged whenever those values match, even if the other columns differ. You can also choose whether the first or the last occurrence survives, and turn off case sensitivity so Alice@example.com and alice@example.com count as one person.
Is my CSV uploaded to a server?
No. The whole deduplication runs locally in your browser with JavaScript — your CSV is never uploaded, stored or logged, and the page keeps working offline once loaded. That makes it safe for customer exports, mailing lists and any file you would not paste into a random website.