Remove Duplicate Lines
De-duplicate any list while keeping the original order.
About the Remove Duplicate Lines
Duplicate entries creep into every list that's been merged, exported or copy-pasted more than once: email lists combined from two campaigns, keyword lists from several research sessions, SKU lists from multiple warehouses, log lines, URLs collected across browser sessions. Sending a campaign to duplicated addresses or importing duplicated SKUs causes real problems — bounces, spam complaints, double-counted inventory — so de-duplication is a step worth doing properly.
Paste your list, one item per line, and this tool removes every repeat while preserving the first occurrence and the original order — unlike spreadsheet de-dupe tricks that sort your data as a side effect. Two options handle the common fuzziness in real lists: case-insensitive matching treats "Apple" and "apple" as the same item (essential for email addresses, where case doesn't matter), and whitespace trimming ignores stray spaces and tabs around entries, which are invisible to the eye but make lines technically different.
The de-duplicated list appears instantly, ready to copy back to wherever it came from or download as a text file. Everything runs in your browser — customer emails and commercial lists are never uploaded. For heavier list surgery, combine this with the neighbouring tools: sort the result alphabetically with the text sorter, compare before-and-after versions with the diff checker, or run find-and-replace to normalise formats before de-duplicating so near-duplicates like "+91 98200 12345" and "9820012345" can be caught.
Frequently asked questions
- Does it keep the original order?
- Yes — the first occurrence of each line stays where it was and later repeats are removed. Nothing is sorted unless you sort it separately.
- When should I use case-insensitive matching?
- For data where case carries no meaning: email addresses, domain names, most codes. Leave it off when case distinguishes real values, like case-sensitive IDs or passwords.
- Why didn't two lines that look identical get merged?
- Almost always invisible whitespace — a trailing space or tab on one of them. Enable the trim option and they'll match.
Related tools
Sort lines alphabetically, by length, or in natural numeric order.
Text Diff CheckerCompare two texts line by line and see exactly what changed.
Find and ReplaceBulk find-and-replace with whole-word, case and regex options.
CSV to JSON ConverterTurn spreadsheet CSV data into a clean JSON array.