How to remove duplicate lines
- Paste your list into the left box, one item per line.
- Choose options: ignore upper/lower case, ignore leading and trailing spaces, remove empty lines, and sort A–Z.
- The cleaned list appears on the right immediately, with counts of lines in, unique lines and duplicates removed.
- Copy the result or download it as a text file.
How duplicates are detected
The tool reads your text line by line and keeps the first time each line appears, removing later repeats. By default, lines must match exactly, so “Apple” and “apple” are different. Turn on Ignore upper/lower case to treat them as the same. Ignore leading/trailing spaces trims stray spaces that often sneak in when copying from spreadsheets, so “ banana ” matches “banana”.
The original order is kept unless you choose to sort, which uses natural ordering so “item 2” comes before “item 10”. Processing happens entirely in your browser, so even long lists of email addresses or customer names stay private.
Where it helps
- Cleaning email or contact lists before importing them.
- Removing repeated keywords from SEO research.
- Deduplicating product codes, URLs or log entries.
- Tidying lists copied from spreadsheets or several sources.
Remove duplicate lines FAQ
Which copy of a duplicate is kept?
The first one. Later repeats are removed, and the order of the remaining lines is preserved.
Can it remove duplicate words within a line?
No. It compares whole lines. Put each item on its own line first, for example with Find and Replace.
How many lines can it handle?
Tens of thousands of lines are processed instantly in a modern browser.