How does duplicate detection work?

The tool compares each line with all previous lines. If a line has been seen before, it is marked as a duplicate and can be removed.

Yes! All processing happens entirely in your browser. Your data never leaves your device or gets sent to any server.

What is case-sensitive mode?

In case-sensitive mode, "Hello" and "hello" are treated as different lines. In case-insensitive mode, they are treated as duplicates.

What does "trim whitespace" do?

When enabled, leading and trailing spaces are removed before comparing lines. This means " hello " and "hello" would be considered duplicates.

Does the tool preserve line order?

Yes, by default the tool preserves the order of first occurrences. The first time a line appears, it is kept in that position.

How are empty lines handled?

You can choose to ignore empty lines (keep all of them) or treat them as duplicates (keep only one empty line).

Can I see which lines were duplicated?

Yes! The tool shows statistics including which lines appeared multiple times and how many times each was duplicated.

What is the maximum file size?

The tool can handle files with thousands of lines. Very large files (over 100,000 lines) may slow down your browser.

Can I use this for CSV data?

Yes, but it compares entire lines. For CSV-specific deduplication based on certain columns, consider using a spreadsheet application.

How do I keep only duplicates instead of removing them?

The tool shows which lines were duplicated in the statistics. You can use this information to extract only the duplicate lines if needed.

How does duplicate detection work?

The tool compares each line with all previous lines. If a line has been seen before, it is marked as a duplicate and can be removed.

Yes! All processing happens entirely in your browser. Your data never leaves your device or gets sent to any server.

What is case-sensitive mode?

In case-sensitive mode, "Hello" and "hello" are treated as different lines. In case-insensitive mode, they are treated as duplicates.

What does "trim whitespace" do?

When enabled, leading and trailing spaces are removed before comparing lines. This means " hello " and "hello" would be considered duplicates.

Does the tool preserve line order?

Yes, by default the tool preserves the order of first occurrences. The first time a line appears, it is kept in that position.

How are empty lines handled?

You can choose to ignore empty lines (keep all of them) or treat them as duplicates (keep only one empty line).

Can I see which lines were duplicated?

Yes! The tool shows statistics including which lines appeared multiple times and how many times each was duplicated.

What is the maximum file size?

The tool can handle files with thousands of lines. Very large files (over 100,000 lines) may slow down your browser.

Can I use this for CSV data?

Yes, but it compares entire lines. For CSV-specific deduplication based on certain columns, consider using a spreadsheet application.

How do I keep only duplicates instead of removing them?

The tool shows which lines were duplicated in the statistics. You can use this information to extract only the duplicate lines if needed.

Remove Duplicate Lines

simple

Remove duplicate lines from text with case-sensitive/insensitive matching, whitespace trimming, and empty line handling. Clean up lists, log files, data exports, and email lists instantly.

Text & Dataduplicatesuniquelinesdedupe

100% Private - Runs Locally

How to Use

1Paste text with duplicate lines
2Choose case sensitivity and trim options
3View unique lines output
4See duplicate statistics

Examples

Simple List Cleanup

Input

apple
banana
apple
cherry
banana
date
apple

Output

apple
banana
cherry
date

Removed: 3 duplicates

Email List Deduplication

Input

john@example.com
jane@example.com
john@example.com
bob@example.com
jane@example.com
alice@example.com

Output

john@example.com
jane@example.com
bob@example.com
alice@example.com

Removed: 2 duplicates

Case-Insensitive Deduplication

Input

Hello
HELLO
hello
World
WORLD

Output

Hello
World

(with case-insensitive option)

Frequently Asked Questions

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