Remove Duplicate Lines

Merged email lists, exported keyword sets, and combined CSV columns are all full of repeats. This tool strips duplicate lines while preserving the original order of the first occurrence, and tells you exactly how many were removed so you can sanity-check the result.

How to use it

  1. Paste your list, one item per line.
  2. Choose whether to ignore case and surrounding whitespace when comparing.
  3. Optionally keep only the lines that appeared more than once instead.
  4. Copy the cleaned list and check the removal count.

Frequently asked questions

Is the original order preserved?

Yes. The first occurrence of each line stays exactly where it was; later repeats are removed. Sort the list first if you want alphabetical output.

Why are lines that look identical not being matched?

Almost always trailing whitespace or a different letter case. Turn on both "ignore case" and "trim whitespace" and they will match.

Can I find the duplicates instead of removing them?

Yes. Switch to "show duplicates only" to list the entries that occurred more than once — useful for auditing data quality before deciding what to delete.

Is there a size limit?

Processing happens in your browser, so it comfortably handles tens of thousands of lines. Very large files are limited by your device’s memory, not by any server.

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