Remove duplicate lines from any list while keeping the original order, with options for case sensitivity and whitespace trimming.
Merged spreadsheets, combined mailing lists, scraped URLs, and repeated log exports commonly end up with duplicate rows. Pasting exported CSV rows as plain text or stitching together two contact lists almost always introduces repeats that are tedious to find by eye in a long file.
This tool is handy for tidying an email or contact list before a mail merge, deduplicating a list of URLs before running a crawler or link checker, and cleaning up log files where the same event line was accidentally captured more than once. In each case, removing duplicate lines first keeps the downstream tool or process from wasting time on repeated data.
"Keep First Occurrence" preserves your original line order and drops every later repeat — the safest default when order matters. "Keep Last Occurrence" keeps that same position but replaces the content with the most recent matching line, which is useful when a later duplicate holds a corrected or updated value.
By default, "Apple" and "apple" are treated as different lines, so a case-sensitive pass can leave near-identical entries behind. Switch to case-insensitive mode when comparing user-entered data like names, emails, or tags where capitalization is inconsistent from one row to the next.
Two lines that look identical on screen can fail to match if one has a trailing space or an extra tab picked up from a spreadsheet paste. Enabling "Trim whitespace" compares lines after stripping the leading and trailing blanks, so those silently different-looking duplicates are still caught, while the original spacing is left untouched in the output.
This tool never reorders your lines — it removes duplicate lines while keeping everything else exactly where it was. That matters because some lists, like a sequence of steps or a set of ranked results, encode meaning in their order and would become misleading if alphabetized.
It is easy to remove duplicate lines from a log file only to discover that lines which looked repeated actually had different timestamps or request IDs hidden further along the row. Always scan a sample of your input first, and use trimming or case-insensitive matching deliberately rather than by default when the source data carries information beyond the visible text.
De-duplication happens locally in JavaScript — your list is never uploaded to a server, so it's safe to use with private data like email lists or internal records.
Quick answers about how this tool works.
"Keep First Occurrence" preserves your original line order and drops every later repeat of a line — this is the safest default for most lists. "Keep Last Occurrence" instead keeps the last time a line appears, which is useful when a later duplicate contains an updated or corrected value.
By default, comparison is case-sensitive, so "Apple" and "apple" are treated as different lines. Enable Case-Insensitive mode to treat them as duplicates instead — useful for lists like names or email addresses where casing is inconsistent.
No. All comparison and de-duplication happen entirely in your browser using JavaScript. Your list is never transmitted anywhere, making it safe to use with private data like email lists or internal records.
Yes, by default it removes duplicates while maintaining the original sequence order of lines.
Plain-language explainers that sit next to this tool.
A blood pressure reading of "120/80" means nothing until you know the categories. Here is the full AHA chart, how ranges shift with age, and when a number becomes an emergency.
A BMI of 25 is "overweight" for a Western adult, but research shows South Asians carry significantly more body fat at the same BMI — and face higher metabolic risk. The WHO recognises lower BMI thresholds for Asians. Here is what the research says and why it matters.
Most Indians accept an EMI figure from their bank without questioning it. This guide explains exactly how Indian banks calculate EMI — the reducing balance method, how RBI repo rate changes flow through to your loan, and what you can do to pay off your home loan years early.
Understand the math behind monthly mortgage payments. Learn how to calculate Principal and Interest (P&I) manually, evaluate the costs of PMI, estimate escrow expenses, and discover strategies to save over $200,000 in lifetime interest.
Search 190+ free tools by name, or pick a category below. Every one runs instantly in your browser — no signup, nothing to install.
Tap a star to rate us instantly.
