How to Remove Duplicate Lines from a List (Keep the Order)
Updated October 2026
Mailing lists, keyword lists and exports from a spreadsheet often contain the same line more than once. Removing the copies by hand is slow and easy to get wrong. Pasting the list into a tool takes a few seconds and the text stays on your own device.
Remove duplicate lines in three steps
- Open the Remove Duplicate Lines tool.
- Paste your list, with one item per line.
- Choose the options you need and copy the cleaned list.
The tool shows how many lines were removed, so you can check that the result is what you expect.
Which copy is kept?
The first time a line appears it stays where it is. Only later copies are removed. That means the order of your list does not change, which matters when the list is already sorted by priority or by date.
If the order does not matter and you want an alphabetical list, sort the cleaned result afterwards.
The three options explained
| Option | What it does | Example |
|---|---|---|
| Ignore upper and lower case | Treats Apple and apple as the same line | Useful for email addresses and keywords |
| Trim spaces at line ends | Ignores spaces at the start and end of a line | Catches lines that look identical but have an extra space |
| Remove empty lines | Deletes blank lines from the result | Handy when the list has gaps |
Without "Ignore upper and lower case", Apple and apple count as different lines. Which setting is right depends on your list: email addresses are normally not case sensitive, while product codes sometimes are.
Why do some duplicates survive?
If two lines look the same but are not removed, the difference is usually invisible. Check for these:
- An extra space at the start or end of one line. Turn on the trim option.
- A different case, such as Apple and apple. Turn on the case option.
- A similar but not identical spelling, such as colour and color. The tool only removes exact copies.
- A different special character, such as a normal hyphen and a long dash.
Privacy
The list is processed in your browser and is not sent anywhere. That is useful for lists of customers or email addresses that you do not want to paste into an unknown website.