Remove Duplicate Lines
Duplicate lines creep into almost every list. You merge two spreadsheets and the same email address appears three times, you copy names from several sources and a few repeat, or you export data from an app and the export includes the same entries twice. Sending that list as it is wastes time and money: the same customer gets the same email twice, the same name is counted twice in a report, and a mailing list looks careless. Cleaning the list by hand works when there are ten lines, but it is hopeless when there are ten thousand. This free tool removes duplicate lines in seconds. Paste your list, choose whether matching should be case-sensitive, whether to sort the result, and whether to drop blank lines, then click the button and copy the clean list. Only the first copy of each line is kept, so the order of your list is preserved unless you ask for sorting. It works on email lists, names, keywords, URLs, product codes, and any other text with one item per line, and it runs entirely in your browser, so your data never leaves your device.
Your Deduplicated List
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All processing is client-side: text never leaves the browser.
How to Use
- Paste your list into the first box, with one item on each line. The sample list is already there so you can try the tool right away.
- Choose your options: leave case-sensitive ticked if "Apple" and "apple" should count as different items, tick sort output to arrange the result alphabetically, and tick remove empty lines to drop blank lines.
- Click Remove Duplicates to clean the list. The result appears in the output box, with the counts below it.
- Click Copy to copy the cleaned list and paste it back into your spreadsheet, document, or email tool.
The options exist because "duplicate" does not always mean exactly the same characters. In an email list, "Sarah@example.com" and "sarah@example.com" are the same inbox, so you should untick case-sensitive matching to catch both. In a list of product codes, "ABC123" and "abc123" might be genuinely different products, so case-sensitive matching is the safe choice. Sorting is useful when you want a tidy alphabetical list, but it destroys the original order, so leave it off when order matters, for example in a ranked list or a list in the order people signed up. Blank lines are usually accidents from copying and pasting, so removing them is almost always a good idea.
Worked Example
Input: five lines — "a", "b", "a", "c", "b".
Output: "a", "b", "c" — three unique lines, with 2 duplicates removed.
Walk through it line by line: the first "a" is new, so it is kept. The first "b" is new, so it is kept. The second "a" has been seen before, so it is removed. "c" is new, so it is kept. The second "b" has been seen before, so it is removed. That leaves "a", "b", and "c" in their original order, and 5 original lines minus 3 unique lines equals 2 duplicates removed. With the default settings — case-sensitive matching on, sorting off, and empty lines kept — paste the sample into the tool and click Remove Duplicates, and you should see exactly "a", "b", "c" and a count of 2 duplicates removed.
Frequently Asked Questions
How do I remove duplicate lines from a list?
Paste your list into the box above and click Remove Duplicates. The tool keeps the first copy of each line and deletes every later repeat, then shows how many duplicates it removed.
Does removing duplicates keep the original order?
Yes, by default the first copy of each line stays in its original place and only later repeats are removed. Tick the sort output box only if you want the cleaned list arranged alphabetically instead.
What does case-sensitive mean for duplicate lines?
With case-sensitive matching on, Apple and apple count as different lines, so both are kept. With it off, they count as the same line and only the first one is kept.
Can this tool remove blank lines too?
Yes. Tick the remove empty lines box and every blank line is deleted along with the duplicates, leaving a clean list with no gaps.
Is my text private when I use this tool?
Yes. This tool runs entirely in your browser and your text is never uploaded, stored, or shared. You can clean private lists, emails, and data without sending them anywhere.