CSV deduplicator
Remove duplicate rows, keep their first occurrence and export CSV.
Local processing · Inputs are not uploadedUTF-8 comma-separated CSV up to 1 MiB. Output uses quoted fields and CRLF, with spreadsheet formula protection.
Preview: up to 20 records, 12 columns and 160 characters per field. Copy and downloads contain all results. Numbers refer to CSV records after skipping blank lines, including the header, not text lines.
Kept record numbers
Removed record numbers
Enter content, then choose an action.
How to use
- Paste comma-separated CSV or select a CSV file.
- By default, compare whole rows and keep the first occurrence, including the first row. Optionally choose a header, key columns and the last occurrence.
- Review kept and removed counts and download both CSV files.
Example
name,city 小林,北京 小周,上海 小林,北京
Frequently asked questions
Will row order change?
Kept and removed records each preserve input order; last occurrence means position, not latest date.
Are commas and line breaks in fields supported?
Quoted CSV fields are supported. Incomplete quotes or inconsistent row widths cause an error.
How are duplicates compared?
Compare exact strings across whole rows or selected columns, preserving spaces and case; 001 and 1 differ. Duplicate headers are distinguished by column position.
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