Remove Duplicate Lines
Strip duplicate lines from a list while preserving the original order.
Lists accumulate duplicates surprisingly easily — merging two spreadsheets of email addresses, combining exported data from different sources, or pasting together notes taken at different times all tend to introduce repeated lines that are tedious to spot and remove by eye, especially in a list of any real size.
This tool removes duplicate lines while preserving the original order and keeping the first occurrence of each unique line — unlike sorting-based deduplication, your list stays in its original sequence, just with the repeats stripped out. An optional case-insensitive mode treats "Apple" and "apple" as the same entry, useful for cleaning up inconsistently-cased data like names or tags.
How to use Remove Duplicate Lines
- 1
Paste your list
Enter your list with one item per line.
- 2
Toggle case sensitivity
Turn on case-insensitive mode if your list has inconsistent capitalization.
- 3
Copy the deduplicated result
The cleaned list updates live and can be copied directly.
Features
- Preserves original line order — no sorting required
- Optional case-insensitive matching
- Keeps the first occurrence of each duplicate
- Instant live processing as you edit
Frequently asked questions
Common mistakes to avoid
- Not enabling case-insensitive mode when a list has inconsistent capitalization, leaving apparent duplicates in the result.
- Assuming leading/trailing whitespace differences won't count as distinct lines — a line with a trailing space is technically different from one without.
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