Remove Duplicate Lines
Paste a list and remove all duplicate lines instantly. Case-sensitive or case-insensitive matching.
What is text deduplication?
Text deduplication (or dedup) removes duplicate lines from a text block. This is useful when working with data lists, log files, CSV data, email lists, or any text where repeated entries cause problems. Instead of manually scanning through thousands of lines, paste your text and get a clean, unique list instantly.
This tool compares lines exactly (by default) and removes all duplicates, keeping only the first occurrence of each unique line. It can optionally ignore case differences (treating 'Hello' and 'hello' as duplicates), trim whitespace, and sort the results alphabetically or numerically.
How to use this tool
Paste your text into the input area. Each line is treated as one item. Click deduplicate to remove all duplicate lines. The tool shows how many duplicates were found and removed. You can choose to preserve the original order or sort the unique lines. Copy the cleaned result with one click.
Deduplication options
- Case-sensitive — 'Apple' and 'apple' are treated as different lines (default).
- Case-insensitive — 'Apple' and 'apple' are treated as duplicates.
- Trim whitespace — removes leading and trailing spaces before comparing.
- Sort output — alphabetically sorts the unique lines in the result.
Common use cases
Cleaning email lists before sending newsletters (duplicate emails waste sending quota and annoy recipients). Deduplicating keyword lists for SEO research. Removing duplicate entries from CSV files or spreadsheet data. Cleaning up log files to find unique error messages. Merging lists from multiple sources into a single unique list.
Frequently asked questions
Does the tool preserve the original order?
Yes, by default the tool keeps the first occurrence of each unique line in its original position and removes subsequent duplicates. If you enable sorting, the output is alphabetically sorted instead. The sort option is useful when the original order does not matter and you want an organized list.
Can I deduplicate based on part of each line?
This tool compares entire lines. For partial matching (like deduplicating CSV data based on one column), you would need to extract that column first, deduplicate, then match back. For simple cases, you can use the trim whitespace option to handle lines that differ only in leading or trailing spaces.