Remove Duplicate Lines

Remove Duplicate Lines is a free browser-based tool that helps you remove duplicate lines from your text. It is part of ToolsMonk's text tools collection, so you can finish the job without downloading software, creating an account, or jumping between multiple websites.

This tool is especially useful for workflows such as de-duplicating a list of emails, urls, or items, cleaning a dataset of repeated rows, and removing repeated lines from logs or exports. Because it runs directly in your browser, you can use it on desktop, tablet, or mobile while keeping the process fast and easy for one-off tasks as well as repeat work.

Remove Duplicate Lines is designed for people who want a practical, privacy-friendly workflow with instant results inside the larger ToolsMonk library.

Remove Duplicate Lines strips repeated lines from a block of text, keeping the first occurrence of each and removing the rest — the quick way to clean a list of emails, URLs, rows, or log lines.

It preserves the original order by keeping each line's first appearance in place, so the list stays as you intended minus the repeats. If you want the result sorted as well, the Text Sorter can sort and de-duplicate together.

A common surprise is lines that look identical but aren't treated as duplicates — almost always because of invisible differences like trailing spaces, tabs, or capitalisation. Enabling whitespace-trimming and case-insensitive matching catches these, which is exactly what you want when de-duplicating things like email addresses where 'A@x.com' and 'a@x.com' should count as one.

Everything runs in your browser, so your data stays private, and the tool reports how many duplicates it removed. Pair it with Text Sorter and Find and Replace in the ToolsMonk text toolkit for full list cleanup.