← Blogby Marcell Almeida

How to remove duplicate rows from a CSV file

Paste CSV and dedupe by full row or a single column — keep first or last occurrence.

Mailing lists and product feeds accumulate duplicate rows after merges. The CSV Dedupe Tool removes duplicates by entire row or a specific column key.

Try it — paste CSV and choose dedupe column

Open full tool →

How it works

  1. Paste CSV — include header row if present.
  2. Dedupe mode — entire row or one column as key.
  3. Copy result — unique rows only.

Key column dedupe

Deduping by email or SKU keeps the first row for each unique key — useful for CRM imports.

Clean first

Run through the CSV Cleaner first so whitespace does not create false unique keys.

The How to remove duplicate rows from a CSV file is free, runs locally, and never sends your data to a server. More converter tools at maratool.com.