CSV Duplicate Row Remover - Dedupe by key columns (free)

Input

Paste CSV / TSV

Rows to output

Delimiter

Key columns (1-based, comma separated. Empty means all columns)

Treat the first line as a header (excluded from matching, kept in output) Ignore leading and trailing whitespace in each cell Ignore letter case Export as TSV (tab separated)

How it works: Quoted CSV (cells containing commas or newlines) is parsed before comparison. Rows are compared cell by cell, so two rows with the same content but different quoting are treated as the same row.

Result

Output

Data rows: 0 Unique rows: 0 Rows removed: 0 Duplicated keys: 0 Output rows: 0

Frequently asked questions

Can I match on specific columns instead of the whole row?

Yes. Enter 1-based column numbers separated by commas in the key columns field. For example "2,3" compares only the second and third columns, so rows differing in other columns are still treated as duplicates. Leave it empty to compare all columns.

Which of the duplicate rows is kept?

The first occurrence is kept. Later rows with the same key are removed. The original order of the remaining rows is preserved.

Does it handle cells that contain commas or newlines?

Yes. Double-quoted cells are parsed before comparison, so commas, newlines and escaped quotes ("") inside a cell are not mistaken for delimiters. Output is re-quoted only where needed.

Is my data sent to a server?

No. Parsing and matching run entirely in your browser with JavaScript. Your data is never sent to or stored on a server.

What is the difference between "Duplicated keys" and "Rows removed"?

"Duplicated keys" counts keys that appear two or more times; "Rows removed" counts the rows dropped in total. If one row appears three times, the key count is 1 and the removed count is 2.

How to use

Paste your CSV — Paste CSV or TSV into the input box on the left. No file upload is needed.
Check the delimiter — The delimiter is detected from the first line by default. Switch to comma, tab or semicolon if the detection is wrong.
Choose the key columns — Leave the field empty to compare all columns, or enter column numbers such as "2,3" to compare only those.
Choose what to output — Pick one of four modes: remove duplicates, duplicated rows only, rows appearing once, or append occurrence counts.
Copy the result — The output box on the right holds the result. Copy it into a spreadsheet or editor.