The best plagiarism checker depends on what you are checking. Students checking an essay before submission are best served by Scribbr or Quetext, writers and SEO teams checking web content by Copyscape or Copyleaks, and publishers who also need AI-content detection by Originality.ai. Universities mostly use Turnitin or Compilatio, which are licensed to institutions rather than sold to individuals. Prices below were checked against each vendor’s own pricing page in October 2026 unless noted.
Plagiarism checkers compared
| Tool | Best for | Free option | Paid from |
|---|---|---|---|
| Scribbr | Students, theses | Basic risk check | About $19.95 per document |
| Quetext | Students and writers | 1,000 words per check | $14.99 per month |
| Grammarly | Everyday writing | Grammar only | Included in Grammarly Pro |
| Copyleaks | Teams, AI detection | Trial | About $13.99 per month, billed yearly |
| Originality.ai | Publishers, AI detection | 3 scans a day | $14.95 per month |
| Copyscape | Web content, SEO | URL search | 3 cents per search |
| PrePostSEO | Budget checking | Limited | $7.50 per month |
| PlagiarismDetector.net | Quick free checks | 1,000 words per check | $9.99 per month |
| Compilatio | Schools and universities | Student account | Institutional quote |
| Turnitin | Universities | No | Institutional licence only |
The 10 best plagiarism checkers
Scribbr
Scribbr is built for students. It checks against Turnitin’s database of web pages and published work, so the result is close to what a university’s own check will show. It charges per document rather than by subscription, priced by word count, with the smallest band listed at about $19.95 for up to 7,499 words in published reviews. Scribbr’s site sits behind a bot check, so we could not confirm the current price directly. The free version gives only a basic risk assessment, not a full report.
Quetext
Quetext checks text against web and academic sources and colour-codes exact matches and near-paraphrases separately. The free plan covers up to 1,000 words per check. Essential costs from $14.99 a month for 100,000 words, and Professional, for teams, from $29.98 a month for 200,000 words. It also bundles an AI content detector and a citation generator.
Grammarly
Grammarly’s plagiarism check is part of its paid Pro plan rather than a separate product. It is convenient if you already use Grammarly to edit, because it works inside browsers, Google Docs and Word. It is weaker than dedicated tools on academic sources. Students who need help beyond checking, such as structuring a long assignment, sometimes turn to services like EssayPro, but check your institution’s rules on outside writing help first.
Copyleaks
Copyleaks detects paraphrased and translated plagiarism as well as exact copies, and adds AI-content detection. It suits teams and education buyers that need an API or LMS integration. Published reviews list the Personal plan at about $13.99 a month billed yearly, with Education and Enterprise plans quoted.
Originality.ai
Originality.ai is aimed at publishers and content agencies that check both plagiarism and AI-generated text. Credits cover 100 words each. The free Basic plan allows 3 scans a day. Pro is $14.95 a month, or $12.95 billed yearly, for 2,000 credits, and Enterprise is $179 a month for 15,000 credits with API access.
Copyscape
Copyscape is the long-standing tool for finding copies of web content. Paste a URL or text and it searches the web for matches. Premium is pay-as-you-go: 3 cents for the first 200 words plus 1 cent for each extra 100 words, so a 1,000-word article costs 11 cents. Copysentry monitors your site for copies automatically, from $4.95 a month for 10 pages with weekly scans.
PrePostSEO
PrePostSEO is a low-cost plagiarism checker inside a larger set of SEO and writing tools. Plagiarism plans start at $7.50 a month for submissions of 5,000 words or more, falling to $6.75 a month when billed yearly.
PlagiarismDetector.net
PlagiarismDetector.net is a quick free checker with a 1,000-word limit per search. Paid plans start at $9.99 a month for 36,000 words, or $4.99 a month billed yearly.
Compilatio
Compilatio is widely used by French-speaking and European schools and universities. Magister is the version for teachers and Studium the version for students, and both flag possible AI-generated text as well as matches. Prices are not published; institutions request a quote, and students can open a free Studium account.
Turnitin
Turnitin is the checker most universities use, and it is sold only to institutions. Its database includes past student submissions, which no consumer tool can match. Turnitin has also absorbed several former rivals: Unicheck was retired after Turnitin bought it, and Ouriginal, the product formed from Urkund and PlagScan, is being phased out in favour of Turnitin Similarity.
How plagiarism checkers work
A plagiarism checker splits your document into short passages and compares each one against an index of web pages, published articles and, for institutional tools, earlier student submissions. It then reports the passages that match and the share of the document they make up. Better tools also catch paraphrasing, by matching on meaning rather than exact wording, and translated plagiarism.
A similarity score is not a verdict. Quotations, references and common phrases all count as matches, so a person still has to read the report and decide whether anything was copied without credit.
Questions about plagiarism checkers
Which plagiarism checker do universities use?
Mostly Turnitin, with Compilatio common in French-speaking countries. Scribbr is the closest consumer option, because it uses Turnitin’s database.
What is the best free plagiarism checker?
Quetext and PlagiarismDetector.net both check up to 1,000 words per search for free. For a full document, the paid per-check options (Copyscape for web content, Scribbr for academic work) are usually cheaper than a subscription.
How do I check a website for duplicate content?
Use Copyscape to find copies of your pages elsewhere on the web, and Copysentry to monitor for new copies. Siteliner, from the same company, finds duplicate text across pages of your own site.
Can plagiarism checkers detect AI-written text?
Some include a separate AI detector, including Originality.ai, Copyleaks, Quetext, Compilatio and Turnitin. AI detection gives a probability, not proof, and can flag human writing by mistake, so treat it as a prompt for review.
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