Duplicate line remover
Paste a list with one item per line. Duplicate lines are removed instantly — the first occurrence of each unique line is kept.
Ctrl + L clear | Ctrl + Shift + C copy output
How to remove duplicate lines from a list
Paste your list into the input box with one item per line — each line is compared independently. The tool instantly identifies every line that appears more than once and removes all occurrences after the first, preserving the original order of your list. This tool works on lines, not sentences within a paragraph — if you need to process a paragraph, first use the line breaks tool to split it into individual lines. The stats bar below the panels shows exactly how many lines you started with, how many are unique, and how many duplicates were removed.
Use the options at the top to fine-tune the behaviour. Case sensitive mode treats "Apple" and "apple" as different items. Trim whitespace ignores leading and trailing spaces when comparing lines so "apple " and "apple" are treated as the same. Remove blank lines strips all empty lines at the same time. Sort output alphabetically reorders the deduplicated list from A to Z.
Common uses for duplicate line removal
Cleaning up email lists is one of the most frequent uses — pasting a list of email addresses and removing every duplicate in seconds. SEO professionals use it to deduplicate keyword lists before uploading to tools. Developers use it to find unique values in log output or configuration files. Data analysts paste spreadsheet columns and remove duplicates without needing Excel or a database query. Writers use it to deduplicate word lists and reference lists.
Case sensitive vs case insensitive deduplication
By default the tool treats lines as duplicates regardless of capitalization. "Apple", "APPLE" and "apple" are all considered the same line and only the first occurrence is kept. This is the right behaviour for most lists like email addresses and URLs where case does not matter. Enable case sensitive mode when your list contains items where capitalization is meaningful — for example a list of programming variables or commands where "getUserName" and "getusername" are genuinely different values.
Frequently asked questions
How does the duplicate line remover work?
The tool compares your text line by line — each line break creates a new item to compare. It keeps only the first occurrence of each unique line and removes all subsequent identical lines. This means your text needs to have one item per line. If you have a paragraph with duplicate sentences, split it into one sentence per line first using the remove line breaks tool, then run deduplication.
Is the duplicate detection case sensitive?
By default the tool is case insensitive so "Apple" and "apple" are treated as duplicates. Enable the case sensitive option to treat them as different lines and keep both.
Will blank lines be removed too?
You can choose. By default blank lines are kept as part of your list structure. Enable the remove blank lines option to strip all empty lines from the output.
What happens to the original order of my list?
The original order is preserved by default. Only duplicate lines are removed — the first occurrence of each line stays in its original position. You can optionally sort the output alphabetically after deduplication.
Can I use this to find unique values in a list?
Yes. This tool keeps one copy of every unique line in your list, which is exactly the same as finding all unique values. Paste your list and the output contains every unique item exactly once.