Remove Duplicate Lines
Clean up your text by deleting repeated lines. Case-insensitive, whitespace-trim and sort options built in — everything runs locally in your browser.
What is the Remove Duplicate Lines?
The Remove Duplicate Lines tool cleans up a list of text lines by removing repeats, leaving only the unique lines behind. You can choose to compare lines case-sensitively or case-insensitively and to keep either the first or last occurrence of each duplicate.
Long lists — email exports, log dumps, keyword sets, phone numbers — often contain duplicates that make deduplication annoying to do by hand. This tool removes them in a single click. You get a clean, sorted or unsorted output ready to paste into a spreadsheet, form or database.
Since everything happens in your browser, sensitive lists (contact exports, customer emails, invoice numbers) never leave your device.
How to use the Remove Duplicate Lines
- 1Paste your list into the input box — one item per line.
- 2Choose whether to ignore case, ignore whitespace or trim each line first.
- 3Pick whether to keep the first or last occurrence of duplicates.
- 4Click "Remove duplicates" and preview the cleaned list.
- 5Copy the result or download it as a .txt file.
Key features
- Case-sensitive and case-insensitive modes
- Optional whitespace trimming
- Optional sorting of the cleaned list
- Keep first or last occurrence
- Live count of duplicates removed
- Runs offline in the browser
Examples
Email list cleanup
Paste 500 email addresses exported from three CRMs and remove duplicates before importing.
Keyword deduplication
Clean an SEO keyword list generated by multiple tools to avoid double-tracking.
Log-file cleanup
Remove repeated error lines from a log dump so you can focus on unique issues.
Why use this tool
- Deduplicates thousands of lines instantly
- Preserves original order or sorts on demand
- Handles case and whitespace differences
- No uploads — safe for private lists
- Free, unlimited and installer-free
Common use cases
- Cleaning CRM and mailing list exports
- Preparing keyword lists for SEO
- Deduplicating logs for post-mortem analysis
- Cleaning phone number lists before bulk SMS
- Removing duplicate URLs from a scrape
- Combining lists from multiple sources
Frequently asked questions
Does the tool sort the output?
Only if you toggle "sort alphabetically". By default the original order is preserved.
Can it remove empty lines?
Yes — enable "remove blank lines" to strip them before deduplication.
Does trimming affect the original data?
Trimming only affects the comparison. The kept line still contains its original whitespace unless you also enable "trim in output".
Is there a maximum list size?
Practical limits depend on RAM. Lists with hundreds of thousands of lines work on desktop.
Is my data uploaded?
No. Deduplication is a pure in-browser operation.