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What does the CSV duplicate remover do?
Upload or paste a CSV and this tool removes duplicate rows, keeping the first copy of each. You decide what counts as a duplicate: an identical row, or rows that share a value in columns such as an email address, optionally ignoring capital letters and extra spaces.
How to use the CSV duplicate remover
- Upload a .csv file or paste CSV text. The delimiter (comma, semicolon or tab) is detected automatically.
- Tell the tool whether the first row contains column headings.
- Choose the column or columns to check. Leave all unticked to compare entire rows.
- Review the original, duplicate and cleaned row counts, then download the cleaned CSV.
Your privacy
Your CSV is read and processed in your browser using the File API. It is never uploaded, so customer lists and other sensitive data stay on your device.
Frequently asked questions
Which row is kept when duplicate rows are removed?
The first occurrence is kept and later copies are removed. The order of the remaining rows is unchanged.
Can I remove duplicates from a CSV based on one column?
Yes. Tick just that column, for example “Email”, and any row whose email has already appeared is removed, even if other columns differ.
How large a CSV file can I clean?
Files of several hundred thousand rows usually work well on a modern computer. The limit depends on your device’s memory, since nothing is processed on a server.
Will the CSV cleaner change my data or formatting?
Kept rows are written back unchanged. The downloaded file uses the same delimiter as your original, with values quoted only where needed.