Remove Duplicate Lines
Remove duplicate lines from any list instantly. Case-sensitive or case-insensitive matching. See exactly how many duplicates were removed.
How to Use
- 1
Paste your list
Enter one item per line in the text box.
- 2
Adjust options
Toggle case-sensitive matching and trim whitespace as needed.
- 3
Copy the result
Duplicate lines are removed instantly — click Copy to use the cleaned list.
How It Works
This tool removes duplicate lines from any list while preserving the original order, keeping only the first occurrence of each line — a quick way to clean up messy lists without manually scanning for repeats.
First-occurrence, order-preserving deduplication
The tool scans line by line, keeps the first time each unique line appears, and discards every later repeat of that same line — the surviving lines stay in their original relative order rather than being alphabetized or otherwise rearranged.
Case sensitivity
With case-sensitive matching on (the default), "Apple" and "apple" are treated as different lines. Toggling case-insensitive matching treats them as duplicates of each other, keeping whichever version appeared first.
Examples
Cleaning an email list
A pasted list with "john@example.com" appearing 3 times keeps only the first occurrence, removing the 2 later duplicates.
Case-insensitive cleanup
With case-insensitive matching on, a list containing both "Apple" and "apple" treats them as duplicates, keeping only whichever came first in the list.
Common Use Cases
- Cleaning duplicate entries from email lists, contact lists, or keyword lists
- Deduplicating exported data before importing into a spreadsheet or database
- Removing repeated lines from log files or scraped data
Tips
- Decide on case sensitivity before pasting a large list — if your list has inconsistent capitalization (like "Email@x.com" and "email@x.com" meaning the same address), turn case-insensitive matching on to actually catch those as duplicates.
- Since the first occurrence is always kept, sort or arrange your list beforehand if you specifically want a particular version of a duplicate (e.g. the most recently added one) to survive rather than the first one.
Frequently Asked Questions
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