Merged email lists, keyword exports, product SKUs, tags copied from several sources: lists collect duplicates quickly, and finding them by eye is tedious and unreliable. This tool removes duplicate lines in one click and gives you a clean list of unique lines that you can copy straight back into your spreadsheet, CMS or code.
Unlike sorting-based approaches, it keeps your order. The first time a line appears it stays in place, and every later repeat is removed. Optional settings let you trim stray spaces, treat upper and lower case as the same and drop empty lines. Everything runs in your browser, so customer emails and internal data never leave your device.
How to use: Remove Duplicate Lines Online
- Paste your list into the Your lines box, with one item per line.
- Keep or untick Trim leading and trailing spaces (on by default).
- Tick Ignore case if "Apple" and "apple" should count as the same line.
- Keep Remove empty lines ticked to drop blank lines, or untick it to keep the first one.
- Click Remove duplicates and check the cleaned list in the Result panel.
- Use Copy or Download to take the unique lines with you.
Example: "Apple, Pear, Apple, Cherry, Pear" on separate lines becomes "Apple, Pear, Cherry".
Common uses for a duplicate line remover
Any list that is built from more than one source is a candidate for deduplication. A few typical examples:
- Email and contact lists merged from several sign-up forms or exports.
- Keyword lists from different SEO tools before you group or upload them.
- Product codes, order numbers or IDs pasted from multiple reports.
- Tags, categories or hashtags collected across many posts.
How duplicates are detected
The tool compares whole lines. Two lines are duplicates only if they are identical from start to end after the options you selected are applied. A line that contains another, such as "apple" and "apple pie", is not a duplicate.
With Trim leading and trailing spaces turned on, spaces at the beginning and end of each line are ignored and removed from the result, but spaces inside the line still matter. With Ignore case, the first spelling wins: if "Apple" comes before "apple", the result keeps "Apple". Accented letters match too, so "Café" and "café" count as the same line.
Compared with Excel and Google Sheets
Excel's Remove Duplicates and Google Sheets' data cleanup tools are great inside a spreadsheet, but they change the sheet in place, and the UNIQUE function needs a formula and a new range. When your list lives in an email, a text file or a CMS field, pasting it here is faster and leaves your original data untouched.
Frequently asked questions
Does the tool keep the original order of my list?
Yes. It walks through your list from top to bottom, keeps the first occurrence of each line where it was and removes later repeats. Nothing is sorted or shuffled. If you would like the result in alphabetical order, sort it afterwards in a spreadsheet or text editor; the unique lines stay unique.
Is the comparison case-sensitive?
By default, yes: "Apple" and "apple" are different lines. Tick Ignore case to treat them as duplicates; the version that appears first is kept. This works for English pairs such as "IT" and "it" as well as accented words. It is especially useful for email lists, where capitalization rarely matters.
What happens to empty lines?
With Remove empty lines ticked, which is the default, every blank line is removed. If Trim leading and trailing spaces is also on, lines that contain only spaces count as empty too. If you untick Remove empty lines, blank lines are treated like any other line, so the first one is kept and the rest are removed as duplicates.
Can it remove duplicate words or comma-separated values?
Not directly, because it compares whole lines; comma-separated values on one line count as a single item. To dedupe them, first put each value on its own line, for example with find and replace in a text editor, replacing commas with line breaks. Then paste the list here. Repeated words inside a single sentence are not removed.
How many lines can I clean at once?
The input limit is 1 MiB, which is tens of thousands of typical lines such as email addresses or keywords. Processing happens in your browser and is usually instant. Your list is never uploaded, so the tool is safe to use with customer data and internal exports.
Will it count how many duplicates were removed?
The tool shows the cleaned list rather than a duplicate count. To see how many lines were removed, paste the original and the result into the word counter and compare the Lines figures. The difference is the number of removed duplicates and, if that option was on, empty lines.