Duplicate Line Remover
Paste a list, get back a clean one: duplicates, empty lines and stray whitespace removed — your text never leaves your device.
Your files never leave your device.
How to remove duplicate lines
- Paste your list into the box — one item per line. It works with anything: emails, keywords, names, SKUs, log entries.
- Pick your options. By default duplicates are removed (case-insensitively), leading/trailing whitespace is trimmed and empty lines are dropped. Turn on Sort A–Z if you want the result alphabetized, or Case-sensitive if Cat and cat should both survive.
- Click Clean list. The result appears below with a summary of how many lines were removed. Copy it or download it as a .txt file.
When is this useful?
- Email and subscriber lists — merge several exports without mailing the same person twice.
- Keyword research — deduplicate keyword exports from different tools before you analyze them.
- Log files — collapse repeated error lines to see which unique events actually occurred.
- Spreadsheets and CSV columns — paste a column, clean it, paste it back. Faster than building spreadsheet formulas for a one-off job.
- Code and data — unique ID lists, tag lists, translation keys.
How it works
The tool reads your text line by line in the browser. Each line is optionally trimmed, then compared against the lines already seen — using a case-insensitive comparison by default, so Apple, apple and APPLE all collapse to the first one that appeared. The first occurrence always wins, which keeps your original ordering intact. If sorting is enabled, the cleaned list is alphabetized as the final step. None of this touches a server: your list is processed in memory and gone when you close the tab.
Exact vs. messy duplicates
Real-world lists are rarely clean. The same item shows up as Apple, apple and APPLE, and a naive "remove exact duplicates" pass keeps all three. That's why trimming runs first: leading and trailing whitespace is stripped before comparison, so lines that differ only by invisible spaces collapse together. The case-insensitive default then handles capitalisation differences. What the tool will not do is guess that Jon Smith and Jonathan Smith are the same person — fuzzy matching like that needs judgment, so the tool stays predictable and only removes lines that genuinely match.
A practical workflow for spreadsheet data: copy the column in Excel or Google Sheets, paste it here, clean it, then paste the result back. For one-off jobs it is far quicker than writing a UNIQUE() formula, removing duplicates via the Data menu, and re-sorting afterwards.
Frequently asked questions
Is my text uploaded anywhere?
No. Deduplication runs entirely in your browser. Nothing is sent to a server, logged, or stored.
Are "Cat" and "cat" treated as duplicates?
By default yes — comparison is case-insensitive, and the first occurrence is kept. Enable the Case-sensitive option to treat them as different lines.
Is the original order preserved?
Yes. Lines stay in their original order unless you enable the Sort A–Z option.
Can I download the result?
Yes — use the Download button to save the cleaned list as a .txt file, or Copy to put it on the clipboard.
Is there a limit on list size?
No artificial limit. Lists with tens of thousands of lines are processed instantly.