Is duplicate matching case-sensitive?
Yes, "Apple" and "apple" are treated as different lines.
Text Tools
Remove Duplicate Lines from a List
Clean a list down to unique lines, keeping the first occurrence of each, right in your browser.
What counts as a duplicate here
This tool trims each line, drops any that end up blank, then keeps only the first occurrence of each remaining unique line — later duplicates are removed while the original order of first appearances is preserved. Because blank lines are dropped rather than deduplicated to one, a list with several empty separator lines will lose all of them, not just the extras.
Comparison is done on the trimmed line text exactly — case matters ("Apple" and "apple" are treated as different lines), and any internal spacing differences within a line (not just leading/trailing) will also make two visually similar lines count as distinct.
Workflow at a glance
Use this quick flow to understand where the tool fits in your work and what to review before relying on the output.
Review checklist
Before
Standardize capitalization first if you want case-insensitive duplicate removal.
After
Confirm the cleaned list's order and check that expected duplicates were actually removed.
When a list needs deduplicating
Use it whenever you have a list — copied email addresses, tags, log entries, or any line-based data — that's picked up accidental repeats, and you want each unique entry to appear exactly once.
Who cleans up duplicate lines
Anyone cleaning a contact or email list
Remove accidental duplicate entries while keeping the list's original order.
Content and tag managers
Deduplicate a list of tags or keywords before using it elsewhere.
Developers cleaning log excerpts
Remove repeated lines from a pasted log or output before analysis.
Anyone merging two lists
Combine lists and remove the overlapping entries in one pass.
What this tool does
Keeps first occurrence order
Unique lines appear in the order they first showed up, not resorted.
Blank lines dropped
Empty lines are removed entirely, not just reduced to one.
Case-sensitive comparison
Lines differing only in capitalization are treated as distinct, not merged.
Instant processing
The deduplicated list updates as you edit the input.
Deduplicating a list step by step
- 1Paste your list into the input box.
- 2Review the deduplicated result as it updates automatically.
- 3Check that case-sensitive near-duplicates were handled the way you expected.
- 4Click Copy output and use the cleaned list wherever you need it.
Where duplicate lines show up
Removing accidental duplicate entries from a contact or email list while keeping its original order.
Deduplicating a list of tags or keywords before using it elsewhere.
Removing repeated lines from a pasted log or output before analysis.
Combining two lists and removing the overlapping entries in one pass.
Where your list goes
Deduplication happens directly in your browser as you edit the list — nothing is sent to a server.
Getting a clean result
- Standardize capitalization first (with Case Converter) if you want "Apple" and "apple" treated as the same entry.
- Remember blank lines are removed entirely here, not preserved as a single blank separator.
- Check for trailing spaces within otherwise-identical lines, since those can prevent a match you expected.
- Combine with Text Sorter afterward if you also want the cleaned list in alphabetical order.
Deduplication mistakes to avoid
Expecting case-insensitive matching
"Apple" and "apple" are treated as different lines — standardize case first if you need them merged.
Not noticing blank lines disappeared entirely
Empty lines are dropped completely, not reduced to a single blank separator.
Assuming trimmed internal spacing counts as identical
Only leading and trailing whitespace is trimmed — differing internal spacing within a line still counts as a different line.
Losing track of original order expectations
The result preserves first-occurrence order, not alphabetical or any other resorting.
Before you rely on the cleaned list
Remove Duplicate Lines is a fast way to clean up a repeated list while preserving the order entries first appeared in. Watch for case-sensitivity and dropped blank lines if the result looks different than expected.
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FAQ
Remove Duplicate Lines FAQ
Answers for using Remove Duplicate Lines on I Love Tool XYZ.
What happens to blank lines?
They're removed entirely, not reduced to a single blank line.
Does this keep the first or last occurrence?
The first occurrence of each unique line is kept; later duplicates are removed.
Is my list uploaded anywhere?
No. Deduplication happens directly in your browser.