Clean up any list in one paste
Merged spreadsheets, combined mailing lists and copy-pasted data almost always end up with repeated entries hiding among hundreds of lines. This free duplicate line remover paste your list and get back a clean, deduplicated version instantly — with options to ignore case, trim whitespace and sort the result alphabetically, all processed locally in your browser.
Why duplicate lines sneak into lists
Duplicates rarely happen on purpose. They creep in when two spreadsheets are merged and the same customer appears in both, when a mailing list is exported twice and pasted together, when a script accidentally appends instead of overwriting, or simply when someone copies a block of text twice by mistake. Individually these are small slips, but across a list of thousands of rows they add up to real, avoidable noise.
What "duplicate" means, and why the options matter
A strict, character-for-character comparison misses near-duplicates caused by inconsistent formatting — which is why the case-insensitive and trim options exist. Without them, "John@Example.com", "john@example.com" and " john@example.com" would all be treated as three different lines, even though they clearly represent the same entry. Turning on case-insensitive matching and whitespace trimming catches these variants and keeps only one clean copy of each.
Where this tool saves time
- Email and contact lists — merging sign-up lists without emailing the same person twice.
- Keyword and tag lists — cleaning up SEO keyword research pulled from multiple sources.
- Code and config imports — removing accidentally duplicated lines from a pasted list of values.
- Spreadsheet exports — tidying a CSV column before importing it somewhere else.
How to use it
Paste your list into the box, toggle case-insensitive and trim-whitespace matching if your data needs it, and the deduplicated result appears immediately, ready to copy. Turn on the sort option if you would prefer the cleaned list in alphabetical order rather than its original sequence.
Deduplication and sorting work well together
Removing duplicates and sorting solve two different problems, and combining them turns a messy, repeated list into something genuinely easy to scan: every entry appears exactly once, and it is easy to find any particular line because the whole list is in a predictable order. That combination is especially useful right before importing a list into another tool — a spreadsheet, a mailing service, a database — where duplicate rows can cause anything from wasted sends to outright errors.
Frequently asked questions
Does it preserve the original order of my list?
Yes, by default the first occurrence of each line is kept in its original position. An optional sort feature is available if you would rather have the result in alphabetical order.
Can it ignore case when checking for duplicates?
Yes. Toggle case-insensitive matching so that 'Email@site.com' and 'email@site.com' are treated as the same line and only one copy is kept.
Does it account for extra spaces at the start or end of a line?
You can enable a trim option so that lines differing only by leading or trailing whitespace are treated as duplicates rather than being kept as separate entries.
Is there a limit on how many lines I can paste?
There is no built-in limit — the tool works entirely in your browser, so the only practical constraint is your device's memory for very large pastes.