Home › CSV tools › Remove duplicate rows
Runs in your browserRemove duplicate rows from a CSV
Merged mailing lists and repeated exports collect duplicates. This removes them either by exact whole-row match, or by a key column — deduplicating on an email or ID column while keeping the first occurrence of each, which is usually what you actually want.
How to use it
- Choose your CSV file.
- Pick a key column to deduplicate on, or leave it blank to match on the entire row.
- Click Remove duplicates. You'll be told how many rows were dropped.
Questions
Is my file uploaded anywhere?
No. This page contains the whole tool — the JavaScript that does the work runs inside your browser tab, on your own machine. There is no server to upload to. You can confirm it yourself: open your browser's developer tools, switch to the Network tab, and run the tool. You will not see your file go anywhere. You can also disconnect from the internet after the page loads and it will still work.
Which duplicate is kept?
The first one, in the order it appears in the file. Later matching rows are removed. If your file is sorted so the most recent record is last, sort it the other way before deduplicating.
Is matching case sensitive?
By default no, and surrounding whitespace is ignored too — so "[email protected] " and "[email protected]" count as the same. Turn on case-sensitive matching if you need exact comparison.