Remove Duplicate Lines Online
Paste your text and instantly remove all duplicate lines. Free, fast and works entirely in your browser.
Frequently Asked Questions
Features
- •Removes repeated lines from text
- •Maintains original formatting and order
- •Works with any text or code
- •Preserves first occurrence of each line
- •Optional case-sensitive or case-insensitive matching
- •Shows exactly how many duplicate lines were removed
How to Use
- Paste your text with duplicate lines
- Turn case-sensitive matching on or off, depending on whether "Email" and "email" should count as the same line
- Click the remove duplicates button
- Review the cleaned output and the count of lines removed
- Copy your deduplicated text
Common Use Cases
- •Clean up comma-separated value lists before importing them elsewhere
- •Remove duplicate entries from a database export
- •Deduplicate a scraped or merged email list before a mail merge
- •Combine two contact lists without ending up with repeated names
- •Clean a keyword list pulled from multiple sources before using it in research
- •Prepare data for analysis and reporting
Frequently Asked Questions
How does Remove Duplicate Lines decide which line to keep?
It keeps the first occurrence of each line and removes every repeat after it, preserving the original order of what remains. It also shows you exactly how many duplicate lines were removed.
Why would duplicate lines end up in my text in the first place?
Usually from merging data: combining two contact lists, appending one export to another, or scraping data from multiple sources. Copy-pasting from spreadsheets is another common cause, especially when a header row gets pasted in more than once.
When should I turn case-sensitive matching off?
When two lines that differ only in capitalization — like "Email" and "email" — should count as the same entry. Case-sensitive matching is the safer default for code or data where capitalization is meaningful; turn it off for lists like names or emails where capitalization is inconsistent but not meaningful.
How do I use the Remove Duplicate Lines tool?
1) Paste your text with duplicate lines 2) Set case-sensitive matching on or off, depending on your data 3) Click the remove duplicates button 4) Review the cleaned output and the count of lines removed 5) Copy your deduplicated text.
What's a common mistake that causes duplicates to survive deduplication?
Trailing whitespace. Two lines that look identical can still be treated as different if one has an extra space at the end — if you're seeing duplicates that should have been caught, check for stray whitespace first.
Does this tool sort my lines too?
No — it only removes duplicates and keeps the remaining lines in their original order. If you also want to sort the result, run it through Text Sorter afterward.
Is my data safe when I use this tool?
Yes. Deduplication happens entirely in your browser — your text is never uploaded to a server.