What problem does this tool solve?
Keyword lists, product exports, and other text data often contain repeated lines. This tool removes duplicate entries with explicit comparison options and reports how many lines remain.
Six practical questions answered
How do I delete duplicate lines from a list?
Paste one entry per line and run the duplicate check. The output keeps one occurrence of each matching entry.
How can I clean up a keyword list without sorting it?
Keep the first-occurrence option selected. Repeated entries are removed while the remaining entries retain their source order.
Can I detect repeated URLs in a pasted list?
Yes. Exact line comparison works by default. Enable URL normalization separately if you want equivalent basic URL syntax to match; no pages are fetched.
How can I remove duplicate email addresses?
Paste one address per line. Choose whether case and leading or trailing spaces should affect matching; the tool does not validate or contact the addresses.
How do I preserve the original order after deduplication?
Select Keep first occurrence. The first copy of each matching line stays in its original position.
How do I see how many duplicate lines were removed?
The result reports the input line count, unique line count, and number removed using your chosen comparison settings.
How it works, with an example
Each full line is one entry. By default, matching is case-sensitive and the first occurrence is retained. Comparison options affect the matching key, not the retained original text.
Practical example
Three lines containing “SEO / SEO / GEO” produce two unique entries and one removed line. Ignoring edge spaces makes “ SEO ” match “SEO”.
Common use cases
- Clean a list of topics.
- Remove repeated text lines.
- Keep the source order of the retained entries.
Limits and considerations
URL normalization uses browser HTTP(S) URL syntax, including host casing and default ports. Path case, query parameters, and fragments remain significant. No live checks or redirect resolution occur. A trailing blank line counts as an entry.
Frequently asked questions
Does duplicate matching distinguish letter case?
Yes by default. You can enable case-insensitive matching.
Can leading and trailing spaces be ignored?
Yes. Enable the trim-for-comparison option; the selected original line is preserved in the output.
Will deduplication preserve list order?
Yes. The retained occurrences remain in their original relative order.
Can I download the deduplicated list?
Yes. Download the actual result as a plain-text file.
Are my uploaded lists stored?
There is no upload. Your pasted lists are processed locally and are not stored by this tool.
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Request a free consultation (German form) →Editorial team: SEOSTUDIO · Updated November 9, 2026 · Tool version 1.1