Remove Duplicate Lines
Paste a list and strip out every duplicate line, keeping the first occurrence. Choose whether to compare case-sensitively and to ignore empty lines.
- Free
- No sign-up
- Runs in your browser
Your text is processed locally in your browser and never uploaded.
How to use Remove Duplicate Lines
- Paste your list, one item per line.
- Choose whether matching should ignore upper/lower case and empty lines.
- Press “Remove duplicates”.
- Copy the cleaned list, or download it as a text file.
About this tool
Email lists, log files and exports often contain the same line many times. This tool keeps the first occurrence of each line and removes the rest, with options that matter for real-world data: case sensitivity, trimming and empty lines.
When to use it: cleaning merged mailing lists, logs or any list where repeats creep in.
Frequently asked questions
Which copy of a duplicate is kept?
The first one, in top-to-bottom order.
Does it trim spaces before comparing?
If you enable “Trim whitespace”, leading and trailing spaces are ignored when comparing lines. Otherwise lines must match exactly.
Does the order of my list change?
No — lines keep their original order; only the later copies of duplicates are removed.
Are blank lines treated as duplicates?
They can be removed with the empty-line option; leave it off if you use blank lines as intentional separators between groups.
Can it clean very large lists?
Yes. Everything runs locally, so lists with tens or hundreds of thousands of lines are processed in seconds.
What is it most useful for?
Deduplicating email addresses, usernames, product codes or log entries — any list where repeats creep in after merging sources.
Related tools
How to use Remove Duplicate Lines
Enter or paste your text into the Remove Duplicate Lines field. Choose the operation — counting, cleaning, sorting, or converting — and apply it. Review the result and copy it back for use.
Practical benefits
- Complete tasks faster without installing additional software.
- Keep files private since processing happens in your browser.
- Produce consistent results that integrate into your workflow.
Frequently asked questions
Is this tool free to use?
Yes. Remove Duplicate Lines is fully free with no account or subscription required.
Does it upload my files?
No. All processing occurs locally within your browser session.
Can I use this for professional projects?
Yes, the tool is designed for both casual and professional use. Always verify critical outputs.