Skip to content

Remove Duplicate Lines

Clean up text files, email lists, CSV data, log files, or any line-based content by removing duplicate lines instantly. The first occurrence of each unique line is preserved. Toggle case-sensitive matching, whitespace trimming, empty line handling, and alphabetical sorting. Everything runs in your browser — your data never leaves your device.

Common Use Cases

Email list cleanup — remove duplicate email addresses before importing to a CRM or email marketing platform. Use case-insensitive matching so "Name@email.com" and "name@email.com" are treated as duplicates. CSV data cleaning — deduplicate rows before analysis or database import. URL lists — remove duplicate URLs from a scraping output or sitemap. Log file analysis — find unique error messages in a server log. Keyword research — deduplicate keyword lists from multiple tools before analysis.

Frequently Asked Questions

What does "case-insensitive" do?+
It treats lines that differ only in capitalization as duplicates. "Apple" and "apple" become one entry. The original capitalization of the first occurrence is preserved.
Does it work with tabs or other delimiters?+
This tool operates on full lines (separated by newlines). For splitting by tabs or commas, use our CSV Viewer or Text Diff tools.

Related Tools

Related ToolSort Lines Alphabetically →

Built by Derek Giordano · Part of Ultimate Design Tools

Privacy Policy · Terms of Service