CSV Deduplicator
Remove duplicate CSV rows locally by full-row match or selected key columns while keeping a clear removal report.
Paste CSV or choose a local CSV file to remove repeated records before importing, sharing, or reviewing a table. Deduplicate by the entire row or by selected key columns, then copy or download the cleaned CSV and review which source rows were grouped together.
Selecting a file replaces the pasted input. Files are read by this page on your device only.
For selected-column mode, enter comma-separated column names or 1-based column numbers.
How to use
Choose the delimiter, confirm whether the first row contains column names, then decide whether duplicates should be found by the entire row or by specific key columns. Key columns can be written as header names, such as email, or as 1-based column numbers, such as 2, 5.
Use first-match mode when the earliest row should win, or last-match mode when later rows should replace earlier rows for the same key. Case-insensitive matching helps with names, emails, and codes that may be typed with inconsistent capitalization.
The output is normalized CSV using the chosen delimiter and line ending. Quoted fields, delimiters inside fields, and line breaks inside fields are supported, but spreadsheet formulas are treated as plain text. Very large files may be slow in a browser tab, and private data should only be opened on devices and pages you trust.
