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CSV Deduplicator

Remove duplicate CSV rows by full comparison or a key column.File & Data Tools

CSV Deduplicator

Remove duplicate rows — by full-row comparison or by a single key column. First occurrences are kept in order.

About this tool

Exact-duplicate rows collapse to their first occurrence. Key-column mode compares just one column — emails, IDs, SKUs — and keeps the first row for each value.

How to use the CSV Deduplicator tool

  1. Add the CSV. Header and data are parsed strictly.
  2. Choose the mode. Whole-row comparison, or name a key column.
  3. Read the counts. Rows kept and duplicates removed are reported before you export.

Supported formats

Input

  • Plain text or file input

Output

  • Converted or analysed output

Inputs are validated before anything is processed. Invalid values and unsupported files are rejected with a clear error instead of failing silently.

Frequently asked questions

Which occurrence is kept?

The first, in its original position.

Is comparison case-sensitive?

Yes, values are compared exactly.

How are blanks treated?

A row of empty cells is still a row and participates in deduplication.

Privacy

Everything you enter stays in this browser tab. There is no upload endpoint for tool inputs, no account, and no server-side copy of your text or files. Results are produced locally and disappear when you close the page.

No account is required and no file is ever uploaded. See the privacy policy for details about analytics and the limited data this site stores.

Known limitations

  • No fuzzy matching; deduplication is exact by design.

Related tools

Other free tools from the same collection.

CSV ViewerView CSV files as a clean table with correct RFC 4180 parsing.CSV EditorEdit CSV cells in a grid and export clean, correctly-escaped CSV.CSV to ExcelConvert CSV into a real .xls workbook with typed numeric cells.Excel to CSVRead .xlsx workbooks locally and export the first sheet as CSV.