Duplikatzeilen-Entferner

Wiederholte Zeilen entfernen — mit Case-unabhängigem Matching, Trimmen, Letztes-behalten und Sortieren.

Optionen

0 lines
0 unique

What is this duplicate line remover?

This is a free, browser-based duplicate line remover that strips repeating lines from any text, with options for case-insensitive matching, whitespace trimming, keeping the first or last occurrence and optional sorting — all running in JavaScript on your own machine, so nothing is uploaded.

How do I remove duplicate lines from a list online without uploading it?

Paste your list and the deduplicated result appears instantly. Toggle case-insensitive matching, trim whitespace before comparing, choose to keep the first or last occurrence and optionally sort. It all runs in your browser — nothing is uploaded.

Key features

Smart matching
Compare lines case-insensitively and ignore leading or trailing whitespace, so visually identical entries are treated as the same.
Keep first or last
Pick which occurrence to preserve — the first time a line appears, or the most recent.
Optional sorting
Sort the deduplicated output alphabetically, useful for cleaning email lists, IDs or imported logs.
Live counts
See the number of original, unique and removed lines update on every keystroke.

How to use it

Paste your lines on the left, one per row. Toggle the options you want — case-insensitive, trim, keep last, sort — and the deduplicated result updates instantly on the right with the line counts. Copy or download the result. Nothing is sent to a server.

Frequently asked questions

Is my data uploaded?

No. Everything runs in your browser, so even sensitive email lists and customer IDs stay private.

Does it keep blank lines?

Repeated blank lines collapse to a single blank line by default since they compare equal; turn on Trim if you want even whitespace-only lines treated as blank.

What is the difference between keeping first and last?

When duplicates exist, keep-first preserves the line where it first appears in your input; keep-last preserves the most recent copy, useful when later entries overwrite earlier ones.

Built by the Toolbox team using a single-pass Set for stable O(n) deduplication and locale-aware case folding, so big lists stay fast and Unicode duplicates are matched correctly.