Remove Duplicate Lines
Paste any list — email addresses, URLs, log entries, CSV rows — and this tool keeps only the first occurrence of each unique line, in the original order. Toggle case-sensitivity and whitespace handling to match exactly how strict "duplicate" should mean for your list.
Why This Tool Matters
You export a mailing list from two different tools, paste both into one document, and now the same email address shows up three or four times scattered throughout a few hundred rows. Scanning line by line to catch every repeat is slow, and it's exactly the kind of task where your eyes start skipping lines after the first hundred. This tool catches every duplicate in one pass — whether it's addresses, URLs, or log entries — so you can paste a clean, deduplicated list straight into your CRM, spreadsheet, or script.
Case sensitivity is the detail that trips people up: turn it off and "[email protected]" and "[email protected]" count as the same duplicate line, which is usually what you want for email addresses since most systems treat them as case-insensitive anyway. Turn it on and those two are kept as distinct lines, which matters for things like case-sensitive usernames or code identifiers where capitalization changes the meaning. Either way, the tool keeps each surviving line's first original occurrence in its original position rather than re-sorting the list, so the order you started with is the order you get back.
How to Use
- 01
Paste your list
Paste your list above.
- 02
Adjust options
Tweak the options if needed.
- 03
Convert & copy
Click to convert, then copy.
More Text Tools
Frequently Asked Questions
Does this preserve the original order of my list?
Yes. This tool keeps only the first occurrence of each unique line and leaves every kept line exactly where it was, so the order of your list never changes.
Can I remove duplicates without caring about capitalization?
Yes. Turn off "Case-sensitive" and lines like "Apple" and "apple" are treated as the same entry, so only the first one you listed is kept.
Will extra spaces at the start or end of a line cause false "unique" matches?
Not by default. "Ignore leading/trailing whitespace" is on by default, so "cat" and " cat" are treated as duplicates. Turn it off if you need whitespace to count as a real difference between lines.
Is there a limit to how many lines I can paste?
No hard-coded limit. The comparison runs entirely in your browser, so it comfortably handles anything from a short list to a large export.
Can I see how many duplicate lines were actually removed?
Yes — the "duplicate lines removed" counter below the result updates with the exact number every time you run the conversion, so you know at a glance whether the list had 3 repeats or 300, without having to compare the before and after lengths yourself.