Remove Duplicate Lines

It scans your pasted text line by line and removes any line that appears more than once, while preserving the order of first appearance. The result is a clean list where each unique line appears exactly once — perfect for cleaning up lists, CSV extracts, email address dumps, keyword lists, and any other repeated data.

It always keeps the first occurrence of each line and discards every later copy. This means the original order of your data is preserved — the first time a line appears stays exactly where it was, and repeated copies are removed from wherever they showed up later.

When enabled, lines that differ only by letter case are treated as the same line. For example, "Apple", "APPLE", and "apple" would be considered duplicates and only the first one would be kept. Leave it off if you need case-sensitive lists where "Apple" and "apple" are distinct entries, such as filenames.

It ignores leading and trailing spaces when comparing lines, so " hello" and "hello" are treated as duplicates even though one has extra spaces. Your original line formatting is still preserved in the output — trimming only affects the comparison, not the text you get back.

When enabled, blank lines are dropped from the result entirely. When disabled, blank lines are preserved as spacing between blocks. Either way, empty lines never count as "duplicates" to be removed, so you can keep your paragraph spacing while still cleaning up repeated content.

Yes. The deduplication runs entirely in your browser using an efficient hash-based lookup, so even lists with thousands of lines are processed in milliseconds with no noticeable lag. Because everything happens locally, there is no file size limit imposed by an upload or a server.

Yes — completely free, no registration, and 100% private. Your text is processed entirely in your browser with plain JavaScript; nothing is ever uploaded, stored, or logged. The tool also works offline after the page loads, so you can clean up lists anywhere.

Yes. The Copy button puts the cleaned output on your clipboard in one click, and the Download button saves it as a .txt file using your browser's native download. You can also see exactly how many lines were removed and which lines repeated most often in the statistics panel.