How Remove Duplicate Lines Works
The tool splits your text into individual lines, then walks through them from top to bottom, keeping a record of every line it has already seen. The first time a line appears it's kept; every later exact repeat of that same line (matching case included) is dropped. The remaining lines are joined back together in their original order.
How to Use This Tool
- Paste your list into the input box, one item per line.
- Select Remove Duplicates.
- Review the cleaned list and the count of duplicates removed.
- Use Copy Result to copy the deduplicated list.
Example
Input "apple\nbanana\napple\ncherry\nbanana" becomes "apple\nbanana\ncherry" — 2 duplicate lines removed, original order preserved.
Helpful Tips
- Matching is case-sensitive, so "Apple" and "apple" are treated as different lines — convert to one case first with the Case Converter if you need case-insensitive matching.
- Blank lines are treated like any other line, so repeated empty lines will also be collapsed to one.
- This is handy for cleaning up email lists, keyword lists, or CSV-exported columns before importing them elsewhere.
Frequently Asked Questions
Is the comparison case-sensitive?
Yes. "Cat" and "cat" are considered different lines and both will be kept unless they match exactly.
Does it preserve the original order of lines?
Yes, the first occurrence of each unique line stays exactly where it was; only later repeats are removed.
What happens to leading or trailing spaces?
Lines are compared exactly as typed, so "cat" and "cat " (with a trailing space) are treated as different lines.
Will empty lines be removed?
Only extra empty lines are removed as duplicates — the first blank line encountered is kept, just like any other line.
This tool runs entirely in your browser. Your input is not uploaded to any server.