Is comparison case-sensitive?

By default, comparison is case-sensitive, so "Apple" and "apple" are treated as different lines. Check the "Case-insensitive" option to treat them as duplicates and keep the first occurrence.

Are leading and trailing spaces considered?

By default, spaces are significant. Enable "Trim whitespace" to strip leading and trailing spaces before comparing, so " hello " and "hello" would be treated as duplicates.

What does the count mode show?

Count mode prepends each unique line with how many times it appeared in the input, formatted as "3x line content". This is useful for finding the most common entries in a log or list.

Line Deduplicator — Remove Duplicate Lines

Line Deduplicator

Remove duplicate lines and optionally count occurrences.

100% in your browser. Your file never leaves your device.

Input (one item per line)

Case-insensitive Trim whitespace Show counts

Type or paste lines above, then click Remove Duplicates.

Why use a line deduplicator?

Duplicate lines appear in log files, exported CSV data, keyword lists, and any text that aggregates entries from multiple sources. Removing them manually is impractical for large files. This tool deduplicates any text in your browser instantly, preserving the original order of first appearances. The count mode is handy for frequency analysis — see which lines appear most often without leaving your browser or touching a spreadsheet.

How to use

Paste your list into the input box. Choose options: enable Case-insensitive to ignore capitalisation differences, enable Trim whitespace to ignore leading or trailing spaces, and enable Show counts to prefix each unique line with its occurrence count. Click Remove Duplicates to process. The output shows only unique lines in their original order.

Preguntas frecuentes

Is comparison case-sensitive?: By default, comparison is case-sensitive, so "Apple" and "apple" are treated as different lines. Check the "Case-insensitive" option to treat them as duplicates and keep the first occurrence.
Are leading and trailing spaces considered?: By default, spaces are significant. Enable "Trim whitespace" to strip leading and trailing spaces before comparing, so " hello " and "hello" would be treated as duplicates.
What does the count mode show?: Count mode prepends each unique line with how many times it appeared in the input, formatted as "3x line content". This is useful for finding the most common entries in a log or list.