About this tool
Remove Duplicate Lines
Free Remove Duplicate Lines tool to clean repeated list items while preserving first-seen order, with optional case, whitespace and blank-line controls.
About the Remove Duplicate Lines
Remove Duplicate Lines cleans lists, pasted data and repeated text by keeping the first occurrence of each line. It is useful for email lists, keyword lists, exports, logs and manually collected data.
How to use this tool
Paste one item per line and choose whether case should be ignored. Run the tool to remove repeated lines while preserving their first-seen order. Empty lines are retained only when they are not considered duplicates of each other by the cleaning routine.
- Open the Remove Duplicate Lines page on Tervilo.
- Enter or paste the text you want to work with.
- Choose any options relevant to the task.
- Run the tool and review the result before copying or publishing it.
How the calculation or transformation works
Two lines are compared as strings after optional case normalization. The first occurrence is preserved and subsequent identical values are removed. This is not a semantic duplicate detector: differently written lines can still represent the same concept.
Common uses
- Cleaning copied lists
- Removing duplicate keywords
- Preparing CSV-like line lists
- Deduplicating simple exports
- Cleaning logs and notes
Privacy and browser-side processing
Tervilo's text tools are designed to process the text in your browser. For ordinary text-editing tasks this can reduce the need to send your content to an application server. Even with browser-side tools, review your organization's security requirements before pasting confidential, regulated or sensitive information into any website.
Related text tools
Explore the Text Tools category for related utilities such as the Word Counter, Character Counter, Case Converter and JSON Formatter.
Frequently asked questions
The FAQ section below covers common questions about this tool, its counting method and practical limitations.
Questions & Answers
Frequently Asked Questions
Does Remove Duplicate Lines preserve the original order?
Yes. The first occurrence is retained and later exact duplicates are removed, so the order of the first occurrences is preserved.
Can duplicate comparison ignore case?
Yes. Enable the ignore-case option to treat uppercase and lowercase versions as the same line.