Duplicate Line Remover
Remove duplicate lines
What Is This Tool?
The Duplicate Line Remover scans a block of text line by line and removes duplicates while preserving the original order of the remaining lines. You can choose whether comparisons are case-sensitive, whether leading/trailing whitespace is ignored, and whether to keep the first or last occurrence of each repeated line.
How to Use
Paste your text, one item per line, into the input box.
Choose case sensitivity, trimming, and which occurrence to keep.
Click Remove Duplicates to see the deduplicated result.
Copy or download the cleaned text.
Features
- Preserves the original relative order of lines
- Optional case-sensitive or case-insensitive comparison
- Optional whitespace trimming before comparing
- Keep first or last occurrence of each duplicate
- Shows a count of removed duplicate lines
- 100% client-side — nothing leaves your browser
Examples
Input:
apple banana apple Banana cherry banana
Output (case-insensitive, trim, keep first):
apple banana cherry
Common Use Cases
- Cleaning up an email or contact list with repeated entries
- Deduplicating a list of URLs, keywords, or tags
- Removing repeated log lines before analysis
- Cleaning up CSV or spreadsheet exports pasted as text
Frequently Asked Questions
Does this change the order of my lines?
No, the original relative order is preserved. Only duplicate lines are removed; the remaining lines stay in the same sequence they appeared in.
What does "Trim whitespace before comparing" do?
When enabled, leading and trailing spaces/tabs on each line are ignored when checking for duplicates, so "apple" and " apple " are treated as the same line. The output still uses the original (trimmed) text.
What's the difference between "keep first" and "keep last"?
"Keep first occurrence" keeps each line's earliest position and removes later repeats. "Keep last occurrence" keeps each line's latest position and removes earlier repeats, which is useful when later entries are more up to date.
Are empty lines treated as duplicates?
Yes, empty lines are compared like any other line, so multiple blank lines will be deduplicated down to one unless you want to keep them separate.
Is my text sent anywhere?
No. Deduplication happens entirely in your browser using JavaScript. Nothing is uploaded or stored.