Remove Duplicate Lines

Remove Duplicate Lines is a free online tool that deletes duplicate lines from any block of text. Paste a list and it keeps the first occurrence of each line while dropping every repeat, so you get a clean, deduplicated result in one click. It works with anything line-based — word lists, CSV columns, log entries, email addresses, URLs, keyword lists, and more.

Use it to dedupe text wherever duplicates pile up: cleaning mailing lists before an import, removing repeated lines from log files, tidying export data, or merging two lists into one unique set. You can keep the original order, or switch to dedupe-and-sort to get unique lines arranged alphabetically. There are also modes to remove empty lines and to trim whitespace from each line before deduping.

Privacy is built in. The entire process runs locally in your browser with JavaScript — your text is never uploaded, logged, or stored on a server. That makes it safe for confidential lists, customer data, and internal logs. Choose preserve-order to keep your list as-is, or sort to normalize it; either way, matching is exact and case-sensitive so you stay in full control of what counts as a duplicate.