Text tool
Duplicate Line Remover
Deduplicate a line-based list locally without sorting it.
Unique lines
What counts as a duplicate here
The text is split into lines on any line break, whether it's a Windows-style CRLF or a plain LF, so pasting from Excel or Notepad doesn't leave stray characters behind. Each line is then compared against every line seen before it, byte for byte, and only the first copy of a repeated line survives — later copies are dropped, but the surviving line keeps its original position in the list.
The comparison never sorts, trims, or lowercases anything on its own. "Apple" as line 4 and "Apple" again as line 9 collapses to one "Apple" sitting at line 4's position; everything else shifts up around it, but nothing is reordered alphabetically.
How the count of removed lines works
Given the input "Apple, Banana, Apple, Cherry" as four separate lines, the output keeps Apple (first occurrence), Banana, and Cherry — three unique lines out of four total, so the tool reports 1 duplicate removed.
Blank lines are deduplicated the same way as text. The input "A", "", "", "B" has four lines but only three unique values (A, an empty line, and B), so three consecutive blank lines in a row would collapse down to just one blank line in the output.
Why two identical-looking lines don't merge
Trailing whitespace is invisible on screen but not to an exact string comparison. "Apple" and "Apple " (with one trailing space) look the same in a text box, but they're six characters versus five, so the tool treats them as two different lines and keeps both.
Case is compared exactly as typed, too — "Apple" and "APPLE" are never merged, since the tool does not lowercase input before comparing. If you need case-insensitive deduplication, lowercase your list in another editor first and paste the result in here.
Situations this is built for
A few concrete cleanup jobs the exact-match comparison handles well:
- Merging two contact lists — 120 pasted email addresses with 15 exact repeats leaves 105 unique addresses
- Combining changelog entries from two branches before a release note
- Deduplicating a keyword export from an SEO tool before building a content plan
- Cleaning a pasted log file where the same error line repeats 30 times in a row
- Merging tag lists exported from two different platforms
- Removing accidental copy-paste repeats from a manually typed list
Frequently asked questions
Does the tool ignore letter case when comparing lines?
No, the comparison is case-sensitive, so "Apple" and "apple" are treated as different lines and both remain in the output. Lowercase your text elsewhere first if you need case-insensitive matching.
Why do two lines that look identical both still appear in the result?
The most likely cause is trailing or leading whitespace — "Apple" and "Apple " with an extra space at the end are different strings even though they render the same way on screen.
Does removing duplicates change the order of my list?
No. The original order is preserved, and each surviving line stays at the position of its first occurrence rather than being resorted.
Are blank lines treated as duplicates of each other?
Yes, an empty line is a value like any other. Three blank lines in a row are three duplicates of the same empty string, so the output keeps only one of them.
Does my pasted text leave my device?
No. The line splitting and comparison happen locally in the browser, and the only way text leaves the page is if you click "Copy result" to put it on your own clipboard.
How is the duplicate count calculated?
It's the number of original lines minus the number of unique lines. Pasting 12 lines that reduce to 9 unique lines reports "Duplicates removed: 3".