Duplicate Line Remover
Remove duplicate lines from any text or list instantly. Options to preserve order, trim whitespace, and ignore case sensitivity.
Runs in your browser. No data leaves your device.
Frequently Asked Questions
How does the Duplicate Line Remover work?
The tool splits your text into lines, then iterates through them while maintaining a Set of seen values. Each line is checked against the Set -- if it has been seen before, it is removed; otherwise it is kept and added to the Set. When case-insensitive mode is on, the lookup key is lowercased before comparison. This preserves original order while running in linear O(n) time.
Does it preserve the original order?
Yes. By default, the first occurrence of each line is kept in its original position and subsequent duplicates are removed.
Is the comparison case-sensitive?
By default, yes. "Apple" and "apple" are treated as different lines. You can toggle case-insensitive mode to treat them as duplicates.
Can I remove duplicates from a CSV or spreadsheet column?
Yes. Paste the column values one per line and the tool removes duplicates. You can then paste the cleaned list back into your spreadsheet.