Yes, completely free with no signup required.

All processing happens in your browser using JavaScript. Your text is never sent to any server. Your file never leaves your browser.

What is case-sensitive mode?

In case-sensitive mode, 'Apple' and 'apple' are treated as different lines and both kept. In case-insensitive mode, they are considered duplicates and only the first occurrence is kept.

What does 'trim whitespace' do?

When enabled, leading and trailing spaces are removed from each line before comparing. This means ' hello ' and 'hello' are treated as duplicates.

Are empty lines removed?

Empty lines are treated as duplicate lines of each other. Enable 'Remove empty lines' to strip all blank lines, or leave it off to keep the first empty line occurrence.

Remove Duplicate Lines Online Free

Deduplicate any list of lines instantly. Browser-based, no signup, nothing uploaded.

🔒 Your file never leaves your browser. All processing is done locally.

Input

Output

Case-sensitiveTrim whitespaceRemove empty lines

How to Remove Duplicate Lines Online

1
Paste your text
Paste or type your list of lines in the input box. Each line is treated as a separate entry for deduplication.
2
Configure options
Choose whether to use case-sensitive comparison and whether to trim leading/trailing spaces before comparing.
3
Copy the deduplicated result
The result updates instantly. Click Copy to copy the deduplicated text to your clipboard.

Duplicate lines appear in many real-world scenarios: merged CSV files, combined log outputs, email lists, keyword research exports, and copy-pasted data from multiple sources. Manually removing duplicates from large lists is tedious and error-prone.

This tool processes the input in your browser in real time as you type — no button click required. The output updates instantly and you can copy it with a single click. For large inputs, the processing is optimised using a hash set for O(n) time complexity.

Frequently Asked Questions

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