Remove Duplicate Lines
Deduplicate a list, and see what was removed.
Remove Duplicate Lines strips repeated lines from a list, optionally ignoring case and surrounding whitespace, and tells you how many it removed. It can also do the opposite — keep only the lines that appear more than once — and show the occurrence count for each unique line. No list is uploaded; the comparison runs on your device.
Loading Remove Duplicate Lines…
Runs entirely on your device. No file or text you enter here is uploaded. How to verify it.
How to use Remove Duplicate Lines
- Paste your list, one item per line.
- Set case and whitespace sensitivity.
- Copy the deduplicated list, or switch to "show duplicates only".
Questions about Remove Duplicate Lines
Does it keep the original order?
Yes. The first occurrence of each line keeps its position; later copies are removed. Sort afterwards with Sort Lines if you want alphabetical order.
Can I find which entries were duplicated?
Yes — the duplicates-only mode lists every line that appeared more than once, with its count, which is how you audit a mailing list or a CSV column.
Does it treat "Alice " and "alice" as the same?
Only if you ask it to. Both trimming and case-insensitive comparison are toggles, off by default so nothing is merged behind your back.
How many lines can it handle?
Lists of a few hundred thousand lines deduplicate in about a second, because comparison uses a hash set rather than checking every line against every other. Past that it is the browser tab, not the method, that becomes the limit.
Is it safe for a customer or mailing list?
The list is never uploaded — the comparison happens in the page and closing the tab discards it. That makes it usable for personal data you would not want to paste into a server-side tool.
Is Remove Duplicate Lines really free, with no limits?
Yes. There is no account, no daily cap, no file-size tier and no watermark, because there is no server cost to recover. The site is funded by clearly disclosed partner recommendations on the Partners page, never by metering the tools.
Are my files or text uploaded when I use Remove Duplicate Lines?
No. Everything is processed by JavaScript running in your browser, on your device. You can verify it: open your browser's developer tools, switch to the Network tab, and use the tool. You will see no request carrying your data — because there is nowhere for it to go.