Remove Duplicate Lines
Delete duplicate lines while keeping the first occurrence.
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About this tool
Mailing lists, keyword lists, log files, and scraped data all collect duplicates over time, and duplicates skew counts, waste sends, and pollute analysis. This tool scans your text line by line, keeps the first occurrence of each unique line, and drops the rest — preserving your original order.
It tells you exactly how many duplicates were removed, so you can verify the result. An optional case-insensitive mode treats "Apple" and "apple" as the same line.
How to use
- Paste your list — one item per line — into the input box.
- Toggle case-insensitive matching if you want it.
- See the deduplicated list and the removed-duplicate count live.
- Copy or download the clean list.
Frequently asked questions
The first one. Later duplicates are removed and the original order of the remaining lines is preserved.
Blank lines are treated like any other line, so multiple empty lines collapse into one. Combine with Remove Empty Lines first if you want them gone entirely.
It treats lines that differ only in capitalization as duplicates — "Apple", "APPLE", and "apple" become one line, keeping whichever appeared first.
No practical limit. It handles lists with tens of thousands of lines directly in your browser.