Remove Duplicate Lines
Remove duplicate lines from text. Options for case sensitivity, whitespace trimming, and empty line handling.
About Remove Duplicate Lines
When you are working with lists — email addresses, CSV exports, log files, code line numbers, search results — duplicates are common and quietly destructive. This deduplication tool takes any block of text, identifies repeated lines, and outputs a clean version with each unique line appearing only once. You can choose whether case differences count, whether to ignore leading and trailing whitespace, and whether to preserve the original order or sort the result.
Useful for cleaning up email lists before a mailing, deduplicating data exports, finding the unique URLs in a sitemap or crawl log, and identifying which lines in a file are not unique (the inverse operation, which the tool also supports). Because everything happens locally, you can safely deduplicate sensitive data without uploading it anywhere.
How to Use
Paste your text with duplicate lines into the input box.
Choose options: case sensitivity, trim whitespace, ignore empty lines.
Click 'Remove Duplicates' to process.
Copy the deduplicated result.
Frequently Asked Questions
How does case sensitivity work?
When case-sensitive, 'Hello' and 'hello' are treated as different lines. When case-insensitive, they're treated as duplicates and only the first occurrence is kept.
What does 'Trim whitespace' do?
It removes leading and trailing spaces/tabs from each line before comparing. This means ' hello ' and 'hello' would be treated as duplicates.
Does this preserve line order?
Yes. The first occurrence of each unique line is kept in its original position. Subsequent duplicates are removed.
Remove Duplicate Lines Online: Deduplicate Text in Seconds (Free)
Got a list with duplicate emails, URLs, or entries? Manually scrolling through to find duplicates is brutal. Our tool deduplicates any text in seconds.
Read the full guide