Runs 100% in your browser — nothing is uploaded
Text & String

Remove Duplicate Lines

Strip repeated lines from a list or text block, keeping either the first or last occurrence.

Remove Duplicate Lines
Client-side

About this tool

Remove Duplicate Lines cleans up lists, log files, or any line-delimited text by eliminating repeated entries while preserving the original order of the lines you keep. Paste a list of emails, URLs, IDs, or any line-based data and get back a de-duplicated version instantly.

Three options control exactly how duplicates are detected and resolved. Case-sensitive comparison, toggled on by default, means "Apple" and "apple" are treated as different lines. Trim whitespace before comparing normalizes away accidental leading or trailing spaces, so "apple " and "apple" are correctly recognized as the same line. Keep-first versus keep-last occurrence determines which copy survives when duplicates are found.

A summary line reports exactly how many duplicates were removed and how many unique lines remain, so you can sanity-check the result before copying it out. All processing happens client-side — nothing is uploaded — making this safe for internal lists or customer data exports.

FAQ

What counts as a "duplicate" line?
By default, two lines are duplicates if their exact text matches, including capitalization and whitespace. You can loosen this with the case-sensitive and trim-whitespace toggles.
Which occurrence gets kept when a line repeats?
By default the first occurrence is kept and later repeats are dropped. Toggle "keep last occurrence" if you want the most recent copy to survive instead.
Does this tool sort my lines?
No, order is otherwise preserved — this tool only removes repeats. Use the Sort Lines tool if you also need alphabetical or numeric ordering.
Can I use this on CSV data?
Yes, for single-column or line-based data it works well. For multi-column CSV where you need to deduplicate based on one specific column, you'd need a spreadsheet tool instead.
Is there a limit on how many lines I can process?
No hard limit is enforced — performance depends on your browser's available memory for very large inputs.