Remove duplicate lines
You can remove duplicate lines here in seconds: paste your text, delete the duplicates and copy the result. Everything runs in your browser and nothing is uploaded.
Source: MDN Web Docs – String.prototype.localeCompare / Intl.Collator (Sortierreihenfolge, numerisch). Updated: .
How it is calculated
The tool keeps every line only once: for duplicates the first occurrence stays, and the order of the other lines does not change.
How lines are compared
By default “Apple” and “apple” count as the same and spaces at the start and end of a line are ignored. With the case option, letter case matters too. Accents and umlauts are recognised in both forms (ä as one character or as a plus a diaeresis).
More options
- Only unique lines: everything that appears more than once is removed completely.
- Only repeated lines: shows what appears more than once, with the count in the table.
- Sort A to Z or Z to A, with numbers in the text in natural order (line 9 before line 10).
All processing happens on your device.
Frequently asked questions
How do I remove duplicate lines from text?
Paste the text into the box. The result shows each line only once, and the first occurrence is kept.
How do I find only the duplicates?
Choose “Only lines that appear more than once”. The table also shows how often each line appears.
Is my data uploaded?
No. The lines are processed in your browser and not stored.
Sources and legal basis
- MDN Web Docs – String.prototype.localeCompare / Intl.Collator (Sortierreihenfolge, numerisch)
- MDN Web Docs – String.prototype.normalize (Unicode-Normalisierung NFC)
- Unicode Standard Annex #15 – Unicode Normalization Forms
As of: · Editorial policy
Related tools
- Alphabetize ListAlphabetize a list online: sort lines A–Z or Z–A, by length or number, remove duplicates and blank lines. Accents sorted correctly; runs in your browser.
- Compare two listsCompare two lists: see what is only in A, only in B or in both. With case, duplicates and sorting options. In your browser, no upload.
- Text CleanerRemove line breaks, extra spaces, empty lines and invisible characters, delete duplicate lines and sort lists. Free, instant and private in your browser.
- Randomize listRandomize a list: put names or items in a new random order, draw winners or split into groups – fair, no sign-up, and your list stays in your browser.
- Add line numbers to textAdd line numbers to text: put a number, letter or Roman numeral before every line, with start, step, separator and leading zeros. Runs in your browser.
- Password GeneratorGenerate secure random passwords and memorable passphrases with entropy shown in bits — calculated right in your browser, nothing sent or stored.
- Emoji copy and paste: click any emoji to copy itEmoji copy and paste in one click: search 1,900+ emojis by group or keyword, pick a skin tone, reuse your recent ones, add kaomoji. Free, in your browser.
- Online teleprompterFree online teleprompter: paste your script, set the speaking pace, go fullscreen and mirror the text for glass prompters. Keyboard control, text stays local.
- ASCII art generatorCreate ASCII art: turn text into big lettering made of characters or convert a photo to ASCII – with width, character set and contrast. Copy or save as .txt.