Duplicate Line Remover
Paste a list, and repeated lines disappear — with control over case, whitespace and ordering.
How to use
- Paste your text or list into the input box.
- Choose options: ignore upper/lower case, trim spaces before comparing, keep original order or sort.
- The cleaned text and the number of removed lines appear instantly — copy the result with one click.
Examples
Clean an email list
Paste 500 addresses collected from several sources; with case-insensitive matching on, John@x.com and john@x.com collapse into one line.
Deduplicate keywords
Merging keyword lists often leaves repeats with stray spaces. Enable trimming so “ shoes” and “shoes” count as the same line.
Cleaning a mailing or contact list
Lists merged from several exports almost always contain the same address more than once, and sending twice to the same person is the visible symptom. Removing duplicate lines before import is faster than deduplicating inside the target system, which often silently keeps the first import.
Deduplicating log or error output
A log full of the same repeated error becomes readable once identical lines collapse to one. What remains is the set of distinct problems rather than their volume — which is the right view when you are trying to find out how many different things went wrong.
Comparing two lists for what is unique
Pasting two lists together and removing duplicates leaves the union with each entry once. Doing it before a comparison makes the next step easier, because you are then working with clean sets rather than lists that contain their own repeats.
FAQ
Which duplicate is kept?
The first occurrence survives; later repeats are removed. With “keep original order” off, the surviving lines are sorted alphabetically instead.
What does the case-sensitivity option change?
When case-insensitive, “Apple” and “apple” are treated as the same line and only the first spelling is kept. When case-sensitive, they stay separate.
How are lines with extra spaces handled?
With “trim whitespace” on, leading and trailing spaces are removed before comparing (and in the output), so “ item ” equals “item”. Turn it off for strict byte-for-byte comparison.
Are blank lines removed too?
Blank lines are treated like any other line: the first blank stays, repeated blanks are removed. This collapses runs of empty lines to one.
Is my text uploaded?
No — deduplication runs entirely in your browser and the text never leaves your device.
Does the original order survive?
Yes. The first occurrence of each line stays where it was and later repeats are dropped, so the output reads in the same sequence as the input. That is usually what you want for lists a person will read; if you need sorted output, sort afterwards.
What about lines that differ only in punctuation?
They are treated as different, because the comparison is on the line text itself. A trailing comma, a different quote mark or a full-width space all make two otherwise identical lines distinct. When a list comes from mixed sources it is worth normalising punctuation before deduplicating.
Can I find the duplicates instead of removing them?
The tool returns the deduplicated list rather than a report of what was removed, but the count tells you how many lines disappeared. If you need to know which entries were repeated, keep the original alongside the result and compare the two — the text diff tool on this site does exactly that.