Remove Duplicate Lines
Paste a list or block of text and strip out every repeated line in one click with full control over what counts as a duplicate.
A merged contact list, a combined email export, or a log file pulled from two sources almost always ends up with the same line sitting in there twice sometimes identical, sometimes just differing by a trailing space or a capital letter that a plain find-and-replace won’t catch. This tool compares every line against every other line, removes the repeats, and tells you exactly how many it found with control over whether “Apple” and “apple” count as the same line or not.
Quick Answer
Paste your list, adjust the case-sensitivity and spacing options if needed, and click “Remove Duplicate Lines.” The tool shows how many lines you started with, how many were removed, and how many unique lines remain.
How to Remove Duplicate Lines
Paste Your List
Paste from your clipboard, upload a .txt file, or drag and drop a file directly onto the box.
Set Your Matching Rules
Decide whether case matters and whether to ignore extra spaces or empty lines when comparing.
Remove and Export
Click “Remove Duplicate Lines,” then copy the cleaned list or download it as a .txt file.
Key Features
Case-Sensitive Toggle
Decide whether “Infolifytool.com” and “infolifytool.com” should count as duplicates or stay separate.
Ignore Extra Spaces
Catches lines that are identical except for trailing or doubled spaces, which a basic comparison would miss.
Ignore Empty Lines
Keep blank lines untouched in the result instead of treating them as one giant group of duplicates.
Before-and-After Count
See your original line count, how many duplicates were found, and how many unique lines remain.
Full Undo/Redo History
Step back through every change, including keyboard shortcuts (Ctrl+Z / Ctrl+Y).
Private by Design
Everything is compared and processed in your browser; nothing is uploaded.
What is “Remove Duplicate Lines”?
Removing duplicate lines means comparing a block of text line by line and keeping only the first occurrence of each one, discarding any repeats. The tricky part isn’t finding exact repeats it’s deciding what counts as “the same” in the first place. Two lines that look identical to a human eye can differ by a single trailing space or a capital letter, which a naive comparison would treat as two different lines entirely. This tool lets you set those rules yourself case sensitivity and whitespace handling so the definition of “duplicate” matches what you actually mean by it.
When Would You Use This?
You merged two contact lists or email exports and need to strip out every address that appears more than once.
You’ve built a keyword list for SEO or ad targeting from several sources and need a single, clean list with no repeats.
You exported data where inconsistent capitalization or stray spaces from copy-pasting created duplicates that a simple comparison wouldn’t catch.
You’re preparing a mailing list or CSV-style list of names and want every repeated entry collapsed into one.
Frequently Asked Questions
Does it treat “Apple” and “apple” as duplicates?
Only if you turn off Case Sensitive. With it on (the default), different capitalization is treated as a different line.
What does “Ignore Extra Spaces” actually fix?
It normalizes repeated or trailing spaces before comparing lines, so two lines that look identical but have invisible spacing differences are correctly caught as duplicates.
What does “Ignore Empty Lines” do?
When enabled, blank lines are left in the result untouched instead of being treated as a group of duplicates and collapsed into one.
Does this tool upload my data anywhere?
No, the comparison and removal happen entirely in your browser.
Can I undo a removal if I used the wrong settings?
Yes, Undo reverts the last change, including the removal step itself.
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