Remove duplicate lines
Clean repeated entries from a pasted list.
Your inputs
Your results
Ready when you areYour results will appear here.
How it works
Remove repeated lines while retaining the first original spelling and order. Compare exact lines or trim surrounding whitespace and optionally ignore case.
Read the source reference ↗A few things to know
Case-insensitive comparison uses JavaScript lowercase, not locale-specific collation. It does not merge spelling variants, normalize Unicode or deduplicate CSV records by key.
When to use this tool
Clean a repeated list deliberately. Trimming and case folding affect the comparison key while the first retained line remains unchanged.
- Clean a mailing list draft.
- Remove repeated keywords.
- Deduplicate a plain-text checklist.
How to use remove duplicate lines
Prepare the inputs
Paste the original text and keep a copy of it.
Choose the settings
Choose the conversion settings; identifiers are preserved as text.
Review and export
Review the output and download it before using it elsewhere.
Try the supplied example
Inputs
text: Apple Banana Apple banana ; case: Sensitive; spaces: Exact; blank: Keep one
Result
With exact, case-sensitive defaults, only the repeated Apple line is removed.
What it means
Choose trimmed case-insensitive comparison to merge the two banana variants.
Common mistakes to avoid
A multiline CSV cell is not a list entry
A multiline CSV cell is not a list entry.
Similar spelling is not an exact duplicate
Similar spelling is not an exact duplicate.
Frequently asked questions
Definitions, edge cases, and practical next steps for this tool. Search all tool FAQs ↗
Does this sort the list?
No. The first-occurrence order is preserved.
Does trimming change the output?
No. It changes comparison only; original retained lines keep their spaces.
Are blank lines duplicates?
Choose to retain one exact blank comparison key or remove blank lines.
Does ignore case handle every language?
It uses JavaScript lowercase, without locale-specific collation rules.
Can I use this on CSV rows?
It compares full lines, not parsed CSV records; multiline cells require a CSV-aware tool.
What is the size limit?
Pasted text is limited to one million characters.
Are my inputs uploaded or stored?
Processing happens locally in your browser. This tool does not upload inputs. Downloads stay on your device; sharing or opening them in another service is your choice.
What should I check before using the output?
Case-insensitive comparison uses JavaScript lowercase, not locale-specific collation. It does not merge spelling variants, normalize Unicode or deduplicate CSV records by key.
Explore the topic in the blog
Sources and method
Use the references below to check definitions and platform guidance. The model’s scope and limits are explained above. Read our editorial standards.