Duplicate Line Remover
Paste your text and duplicate lines disappear as you type.
Options
Processed on your device — nothing is sent anywhere.
How it works
- Paste or type your text into the input box on the left.
- The cleaned text appears instantly on the right, keeping the first occurrence of each line.
- Open Options to ignore case or surrounding whitespace, then press Copy to grab the result.
Frequently asked questions
- Which copy of a duplicate line is kept?
- The first occurrence is always kept and every later repeat is removed. The original order of your lines is preserved, so nothing gets sorted or rearranged — the output is simply your text minus the repeats.
- What does the case-insensitive option do?
- With it enabled, lines that differ only in letter casing count as duplicates, so “Apple” and “apple” become one line. The kept line always retains its original casing; the option only changes how lines are compared, not how they look.
- Can I remove duplicates from a spreadsheet column or CSV?
- Yes — copy the column and paste it here; each cell arrives as its own line, so duplicates are removed the same way, and you can paste the cleaned result back into the spreadsheet. For whole CSV rows, paste the full lines; two rows only count as duplicates when the entire line matches.
- Is there a limit on how much text I can paste?
- There is no fixed limit. The comparison runs in your browser’s memory, so lists with tens or even hundreds of thousands of lines are handled comfortably on a normal computer. Only truly enormous texts are constrained, and by your device’s memory rather than by any server-side cap.
- Is my text uploaded anywhere?
- No. Everything runs locally in your browser using JavaScript, and the page makes no network requests with your content. You can even load the page, disconnect from the internet, and the tool keeps working.
About this tool
This duplicate line remover cleans repeated lines out of any text in real time. Paste your content into the left box and the deduplicated version appears on the right immediately, keeping the first occurrence of every line and preserving the original order. Options let you treat lines as equal regardless of letter case or of leading and trailing whitespace, and a Copy button grabs the finished result.
The comparison runs entirely in your browser: each line is checked against the set of lines already seen, all in local memory, with no network requests carrying your content. That makes the tool appropriate for text you would not want on someone else’s server — email lists, customer records, exported logs — and it keeps working even if you go offline after loading the page.
Deduplication comes up more often than people expect: merging mailing lists that overlap, tidying keyword lists for ads or SEO, cleaning URL or domain collections scraped from several sources, reducing repetitive log output to its unique messages, and consolidating to-do or inventory lists assembled from multiple files. In every case the whole job — paste, glance at the result, copy it back out — takes a few seconds, with no spreadsheet formulas or command-line tools required.
Two options cover the usual gotchas. If near-identical lines survive, invisible whitespace is the usual culprit — enable the whitespace option so “item ” and “item” match. If casing varies across sources, enable case-insensitive matching so “London” and “london” collapse into one entry while the kept line still keeps its original look.