Remove Duplicate Lines
Instantly deduplicate text — remove repeated lines, sort results, trim whitespace, and clean up your data.
Free Online Duplicate Line Remover
This tool removes duplicate lines from any text, keeping only unique entries. It's essential for data cleaning, list deduplication, log file analysis, email list cleanup, and preparing CSV data. Paste your text, click "Remove Duplicates," and get clean, unique lines instantly.
How It Works
The tool reads your text line by line and tracks which lines have already appeared. When a duplicate is found, it's removed from the output. The original order of first appearances is preserved unless you enable sorting. All processing happens in your browser — your data is never uploaded anywhere.
Options Explained
Ignore case treats "Apple" and "apple" as the same line. Trim whitespace removes leading and trailing spaces before comparing, so " hello " matches "hello". Remove empty lines strips blank lines from the output. Sort A→Z alphabetically orders the unique results. Reverse order flips the output.
Common Use Cases
Clean up email lists by removing duplicate addresses. Deduplicate CSV data before importing. Remove repeated log entries for analysis. Clean keyword lists for SEO work. Prepare unique data for database imports. Remove duplicate URLs from link lists.
Frequently Asked Questions
No hard limit. The tool processes tens of thousands of lines efficiently since everything runs in your browser. For very large files (100K+ lines), processing may take a few seconds.
Yes, by default. The first occurrence of each line is kept in its original position. Only subsequent duplicates are removed. Enable "Sort A→Z" to alphabetically reorder the results.
Yes. Check "Ignore case" to treat uppercase and lowercase as the same. For example, "Hello" and "hello" would be considered duplicates, and only the first one would be kept.