Remove Duplicate Lines
Remove duplicate lines from any list instantly, with case-insensitive matching, trim, sort and duplicates-only modes.
0 lines in · 0 lines out · 0 duplicates removed
How it works
Paste a list into the top box and every duplicate line is removed instantly — the first occurrence of each line is kept and the original order is preserved, so you never have to sort your data just to deduplicate it. Trim spaces is on by default, because lists pasted out of a spreadsheet or an email carry trailing spaces that hide duplicates from view — turn it off if the spacing matters. Turn on Ignore case to treat "Apple" and "apple" as the same entry, and Remove empty lines to drop blank rows. You can also flip the tool around: choose "Keep only the duplicates" to find the repeated entries in a list, or "Keep only the one-offs" to keep just the entries that appear exactly once. The counter under the boxes always describes the mode you are in.
Everything runs as plain JavaScript in your browser — your list is never uploaded to a server, which makes it safe for emails, customer records, log files, keyword lists and anything else confidential. Use Copy result or Download .txt to take the cleaned list with you.
Frequently asked questions
How do I remove duplicate lines from a list?
Paste your list into the top box, one entry per line. The result box below updates instantly with every duplicate line removed. The first occurrence of each line is kept and the original order is preserved. Then use Copy result or Download .txt to take the cleaned list with you.
Can it treat "Apple" and "apple" as the same line?
Yes. Tick "Ignore case" and lines that differ only in capitalisation count as duplicates, so only one of them is kept. Tick "Trim spaces on each line" as well if stray leading or trailing whitespace might be hiding duplicates in your data.
Can I see only the duplicate lines instead of removing them?
Yes. Switch "What to keep" to "Only lines that appear more than once" to list just the duplicated entries, or to "Only lines that appear exactly once" to keep only the one-off lines. The counter always shows how many lines went in, how many came out and how many duplicates were removed.