CSV or Excel tool
Remove CSV Duplicates
Remove repeated rows from a CSV while keeping the first occurrence. Compare every column, or only the key columns you name, with optional case and whitespace handling.
Add files
Drop CSV files here, or choose files. Everything stays on this device.
Waiting for files
Accepted input
- CSV or TSV files
Limits
- Up to 20 MB per CSV/Excel file and up to 100000 rows.
- CSV, TSV, XLSX and JSON inputs are supported in this category.
Local processing
- Files are read in your browser and are never uploaded to a server.
- Nothing is stored after you close or reload the page.
How to use Remove CSV Duplicates
- Add a CSV file.
- Optionally enter the zero-based key column indexes, for example 0 for the first column.
- Adjust case and whitespace rules, then press Remove duplicates.
What it does
- Keeps the first occurrence and removes later duplicates.
- Can compare the whole row or only the columns you list as keys.
- Reports how many rows were removed, and can ignore case or surrounding spaces.
Limits and things to know
- The comparison is exact after the chosen normalisation; it does not detect near-duplicates.
- Only rows are removed, never columns.
Example
De-duplicating a contact list
A file lists alice@test.com twice. Leave the key blank to compare the whole row and remove the second copy, keeping the first. Enter 0 to compare email only when other columns may differ.
Frequently asked questions
Which duplicate is kept?
The first occurrence in file order is kept; every later match is removed.
How do I compare only one column?
Enter its zero-based index, for example 0 for the first column, in the key columns field. Blank means compare all columns.
Does it change column order or headers?
No. Headers and column order are preserved exactly; only duplicate data rows are dropped.
Runs entirely in your browser on ap98.com. Files are never uploaded.