Duplicate Line Remover
Paste any list, remove duplicate lines instantly, and optionally sort or trim. Shows line count before and after so you can see exactly what was removed.
When to Use a Duplicate Line Remover
The most common use case in SEO: cleaning up keyword lists. Export keywords from multiple tools, paste them all together, remove duplicates, and you have a clean consolidated list ready for analysis or import. Same workflow applies to URL lists from crawlers, domain lists, and email contact lists.
Options explained
- Remove duplicates — Core function. Keeps the first occurrence, removes subsequent ones. Order preserved.
- Sort lines — Alphabetical sort (A-Z). Runs after deduplication if both are selected.
- Remove empty lines — Strips blank lines from the output. Useful when pasting from Excel or CSV exports.
- Trim whitespace — Removes leading and trailing spaces from each line before comparison. This means " hello " and "hello" will be treated as duplicates.
Frequently Asked Questions
What is a duplicate line remover used for?
It's commonly used to clean up keyword lists (removing duplicate keywords before importing to ad tools), email lists (deduplicating contacts), domain lists, URL exports from crawlers, code arrays, and any other list-format data where duplicates need to be removed before processing. It's a staple tool for SEOs working with large keyword spreadsheets.
Does the tool preserve line order?
When deduplication only is selected, the first occurrence of each line is kept and subsequent duplicates are removed, preserving the original order. When Sort Lines is selected, lines are sorted alphabetically after deduplication. You can run deduplication without sorting if order matters to you.
Is the comparison case-sensitive?
By default, comparison is case-sensitive, so 'Hello' and 'hello' are treated as different lines. Most tools handle it this way because case differences in URLs, keywords, and code often matter. If you want case-insensitive deduplication, convert everything to lowercase first using our Case Converter tool, then deduplicate.
How many lines can I process at once?
The tool runs entirely in your browser — there's no server-side limit. In practice, it handles tens of thousands of lines without issue. Very large inputs (100,000+ lines) may cause a brief delay on older devices, but there's no hard cap imposed by the tool itself.
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