How are duplicates defined?

Rows are duplicates when every column matches exactly. Comparison happens after trimming.

The first occurrence; later copies are removed.

Can I deduplicate on one column only?

Not in this release. You can hide other columns to compare more narrowly, but full-row comparison is the default.

Is the row order preserved?

Yes, the surviving rows keep their original order.

Remove duplicate rows from a CSV

Turn on Deduplicate and repeated rows collapse to their first occurrence. Detection runs after whitespace trimming, so two rows that differ only by a trailing space are still treated as duplicates.

A badge shows how many rows were removed, and the export contains exactly what you see in the preview. The whole operation is client-side.

Markdown / CSV Output

Drop a file to clean and export it

Processing stays in this browser. Guests can process up to 500 rows per file.

How to use this tool

1Drop the CSV that has duplicate records.
2Turn on Trim Whitespace first, then Deduplicate.
3Watch the badge count for how many rows were removed.
4Download the deduplicated CSV.

Frequently asked questions

How are duplicates defined?: Rows are duplicates when every column matches exactly. Comparison happens after trimming.
Which copy is kept?: The first occurrence; later copies are removed.
Can I deduplicate on one column only?: Not in this release. You can hide other columns to compare more narrowly, but full-row comparison is the default.
Is the row order preserved?: Yes, the surviving rows keep their original order.

Private by design

This tool runs entirely in your browser. Files, tables, and results are never uploaded to a server — you can even disconnect your network and keep working. See the Privacy Policy.