Detect and remove duplicate lines from text instantly. Choose how duplicates are handled, sort results, and view detailed frequency analysis. Fast, free, and private.
Intelligent line deduplication & frequency analysis utility
The Remove Duplicate Lines tool is a high-performance, free online utility that scans your text line by line to identify and eliminate repeated entries. Whether you are cleaning a data list, deduplicating email addresses, tidying up code output, or processing log files, this tool gives you precise control over how duplicates are handled.
It offers three removal modes, flexible comparison options (case sensitivity, whitespace handling), post-processing sort/shuffle capabilities, and a detailed frequency report. All processing runs 100% locally inside your browser for complete privacy and instant speed.
Common scenarios where duplicates cause problems
Spreadsheet exports, CSV files, and database dumps often contain repeated rows that need deduplication before analysis.
Mailing lists and contact exports frequently have duplicate addresses that inflate counts and cause double-sends.
Duplicate import statements, repeated CSS rules, or redundant config lines clutter codebases and cause conflicts.
Server logs and error reports contain repeated entries that obscure unique issues and slow debugging.
Keyword lists, tag collections, and editorial notes accumulate duplicates during collaborative editing.
Training data, prompt templates, and automation scripts must be deduplicated to avoid bias and wasted processing.
Built for speed, flexibility, and precision
Tailored for professionals and everyday text tasks
Deduplicate datasets, CSV exports, and query results before importing into analytical platforms.
Clean up log files, remove redundant imports, and normalize configuration entries.
Deduplicate keyword lists, email campaigns, and audience segments.
Remove repeated headings, bullet points, and notes from collaborative drafts.
Clean reference lists, bibliographies, and extracted data from multiple sources.
Validate unique entries in SQL dumps and bulk data exports.
How comparison options affect which lines are considered duplicates
Lines are compared after converting to lowercase. “Apple”, “apple”, and “APPLE” are treated as the same line.
Apple → kept
apple → removed
APPLE → removed
Lines are compared exactly as written. Different capitalizations are treated as distinct lines.
Apple → kept
apple → kept
APPLE → kept
Simple 5-step workflow to deduplicate your text
Paste text or drag & drop a .txt file into the input box.
Select Keep First, Keep Last, or Remove All Duplicates.
Configure case sensitivity, whitespace, and sort preferences.
Check the output, statistics, and duplicate frequency report.
Copy to clipboard or download as TXT, CSV, JSON, or Markdown.
See how each mode handles different duplicate scenarios
Apple Banana Apple Orange Banana Mango
Apple Banana Orange Mango
Apple Banana Apple Orange Banana Mango
Apple Orange Banana Mango
Apple Banana Apple Orange Banana Mango
Orange Mango
Apple apple APPLE Banana
Apple Banana
Cherry Apple Banana Apple Cherry
Apple Banana Cherry
Your data stays on your device
All text processing occurs entirely in your web browser. Your text is never transmitted to any server, never stored in any database, and never logged or analyzed. There are no cookies tracking your content, no analytics capturing your text, and no server-side processing of any kind. Close the browser tab and your data is completely gone. This tool is safe for sensitive, confidential, and proprietary content.
Everything you need to know about duplicate line removal
