Built for students, writers and researchers
Plagiarism Checker by ZeroTell · see every source
Paste your text and we check its sentences against pages on the web. Matching passages are highlighted, with a link to each page they were found on.
Plagiarism report
Your report will appear here: a similarity score, the matching sentences and links to their sources.
How the Plagiarism Checker works
We split your text into sentences
Longer sentences carry the most distinctive wording, so they are the ones we search for.
The sentences are checked against the web
Every eligible sentence of a typical essay is looked up on public web pages. Very long texts are sampled evenly from start to end.
Results are compared phrase by phrase
A sentence counts as a match when a large share of its three-word phrases appear on a page that was found.
You review the sources
Matching sentences are highlighted and every source is linked, so you can judge each one yourself.
What you get in every report
Who uses it
Students
Check that quotes are cited and paraphrases are your own before you hand in an essay.
Writers and bloggers
Make sure a draft doesn't echo an article you read while researching.
Teachers
Spot passages that appear elsewhere online and open the source to compare.
Marketing teams
Confirm that agency or freelance copy is original before it goes live.
Fix what the report finds
Rewrite matching passages in your own words, then check again.
Frequently asked questions
Public web pages, found through our plagiarism search provider. It does not search private databases, paywalled journals or other students' submissions, so a clean report is not a guarantee that the text is original.
Sentences of at least 8 words are checked. A typical essay of up to about 3,000 words has every eligible sentence checked, and texts over 6,000 words are sampled evenly across the whole document. Links, table rows and repeated lines are skipped, and the report always shows how many sentences were checked.
Yes. "Exclude quotes and references" is on by default: text inside quotation marks ("…", “…”, «…», 「…」) and a reference list at the end (References, Bibliography, Works Cited, 参考文献 and similar headings) are left out of the search, the score and the price. The report says what was excluded. Switch it off to check everything.
Yes. Upload a PDF, Word (.docx), TXT or Markdown file up to 10 MB, or paste the text. One check takes 15 to 15,000 words. Scanned PDFs that are only images can't be read — paste the text instead. The file is only used to extract the text and is not stored.
It is the share of the checked sentences, by length, that matched a web page. A sentence matches when a large share of its three-word phrases (five-character runs in Chinese and Japanese) appear on that page.
No. Turnitin and similar services compare against their own databases of submitted papers. ZeroTell only checks the public web and shows you the pages it found.
Not on the Pro plans* (*fair use counts the sentences a check searches: up to 1,000 a day). Without a plan, credits you already have pay for a check: 2 credits for up to 1,000 words, plus 1 credit for each further 1,000 words, at most 7 credits. Excluded quotes and references don't count toward the words. In Chinese and Japanese, each character counts as one word (as in Microsoft Word). If part of a check fails, the credits or fair use for that part are returned. Without a plan or credits — signed in or not — you get 1 free check a day of up to 500 words; it searches at most 30 sentences, and the report says how many were checked.
The sentences being checked are sent to our plagiarism search provider to run the check (see the Privacy Policy). We do not publish your text or add it to any database.
Know your sources before you submit
Paste your text and see which sentences already exist on the web.
Check for plagiarism