Remove Duplicate Lines
Paste a list, remove every duplicate line, and get a clean, unique list back — with sorting options.
What is this tool?
Duplicate lines creep into every list: email subscribers exported from two tools, keyword lists merged from spreadsheets, product SKUs, student rosters, inventory counts. Manually hunting repeats in a thousand-line list is slow and error-prone. This tool removes duplicate lines instantly, keeping the first occurrence of each line, and reports exactly how many duplicates it removed.
Options cover the real-world messes: ignore case so 'Apple' and 'apple' count as the same entry, trim whitespace so trailing spaces do not hide a duplicate, and sort the cleaned list alphabetically. Everything runs in your browser, so customer emails and other private lists are never uploaded to a server.
How to use it
- Paste your list into the input box, one entry per line.
- Choose options: sort alphabetically, ignore case, or ignore surrounding spaces.
- Click Remove duplicates and copy the cleaned output.
Formula & method
Worked example
A mailing list with 'john@example.com' appearing three times, plus 'JOHN@example.com' once, becomes a single entry with the ignore-case option on — four lines in the raw list, one clean subscriber in the output.
Frequently asked questions
Can I dedupe an email list before importing it?
Yes — that is one of the most common uses. Clean the list here first and your email platform will not charge you for duplicate contacts or bounce the import.
Does it keep the original order?
By default yes: the first occurrence stays in its original position. Turn on Sort alphabetically if you prefer A-to-Z output instead.
Is there a size limit?
Practically no for normal lists. Because it runs locally in your browser, even lists with hundreds of thousands of lines process in a second or two.