The best plagiarism checkers, tested and ranked

Plagium came first of six with 3 out of 5. It got 40 of our 50 documents right, missed 7 of the 30 with copied text and wrongly flagged 3 of the 20 original ones. At 21.7 seconds per document, it was the quickest in the test. Our full Plagium review has the details.

Plagium offers a Quick search of the live web, news and academic sources, and a Deep search that adds archives and can catch translated matches. It also estimates whether text was written by AI, as a probability rather than a verdict. Pricing is flexible: free users get 2 searches a day of up to 2,000 characters, or 5 with an account, and single documents cost from $2 for 1 to 5 pages. You can also buy credits that never expire, from $7.95 for 25, or take the Unlimited plan at $19.98 a month.

We couldn't find how Plagium handles the text you submit, and it has only 2 reviews on Trustpilot (3.3 out of 5, checked November 2026), one about an unanswered refund request. That's too few to judge it by.

Quetext came second with 3 out of 5, level with Plagium, and had the highest accuracy score in the test. It got 41 of 50 documents right, missed only 6 of 30 copies and wrongly flagged 3 of 20 originals. It took 25.5 seconds per document. Read our Quetext review for the full test.

Quetext uses its own DeepSearch method to find exact, near and paraphrased matches, and bundles an AI detector, summarizer, humanizer and grammar check in the same plan. Instead of paying per document, you buy a monthly word allowance. The free plan checks up to 1,000 words, Essential is $14.99 a month for 100,000 words, and Professional is $29.98 a month for 200,000 words with unlimited users.

Its privacy policy says your text may be used for AI training unless you opt out by email. Users rate it highly, at 4.6 out of 5 on Trustpilot (154 reviews, checked November 2026), praising how easy it is to use and how quickly support replies.

PlagiarismCheck.org came third with 2.5 out of 5. It got 38 of 50 documents right, missed 8 of 30 copies and wrongly flagged 4 of 20 originals. At 27.9 seconds per document, it was the second slowest. It scored 3 for ease of use and for false positives, and by default it leaves properly cited references out of the score. Our PlagiarismCheck.org review covers it in depth.

Its strength is schools. It works inside seven learning platforms, including Moodle, Canvas, Brightspace and Google Classroom, and has a Google Docs add-on, a Chrome extension and an API. School plans, sold by quote, add an authorship check that compares a writer's style across submissions. It also has an AI checker called TraceGPT.

For individuals, the pricing is unclear. Packs are listed at $5.99, $9.99, $25.49 and $45.49, but the pricing page doesn't say what each includes or whether you pay once or repeatedly. There's a free 2-page check. Users rate it well, at 4.4 out of 5 on Trustpilot (90 reviews, checked November 2026).

SmallSEOTools came fourth with 2.5 out of 5. Like PlagiarismCheck.org, it got 38 of 50 documents right, missed 8 of 30 copies and wrongly flagged 4 of 20 originals. It took 26.6 seconds per document. Our SmallSEOTools review explains each result.

SmallSEOTools is a website full of free tools, and the plagiarism checker is one of many. Free scans cover up to 1,000 words. Pro Monthly is $9.80 a month, or Pro Yearly works out at $7.84 a month, billed yearly, and Pro raises the limit to 30,000 words per scan and adds a WordPress plugin. Reports show exact and partial matches, and you can leave up to 10 web addresses out of a check.

The site says your text is used only to make the report and stays confidential, but gives no retention period. On Trustpilot it has 2.9 out of 5 from just 15 reviews (checked November 2026), with complaints about tools failing without an error.

Copyscape came fifth with 2 out of 5. It got 37 of 50 documents right, missed 9 of 30 copies and wrongly flagged 4 of 20 originals. It was fairly quick, at 23.7 seconds per document. Our Copyscape review has the full results.

Copyscape is built to find copies of web content on the public web, using Google as its search provider. That suits publishers checking freelance articles and site owners hunting for scraped pages, but it doesn't search academic papers. Premium is prepaid, with no subscription: 3 cents per search of up to 200 words, plus 1 cent for each extra 100 words. It adds Batch Search for up to 10,000 pages, an API and a Private Index for checking against your own content. A free search for web addresses shows up to 10 results.

It has only 6 reviews on Trustpilot, with 2.4 out of 5 (checked November 2026). Copyscape itself warns that its AI detector can be inaccurate.

Scribbr came last of six with 2 out of 5. It got 36 of 50 documents right, missed 10 of 30 copies, the most in our test, and wrongly flagged 4 of 20 originals. At 29.9 seconds per document, it was also the slowest. Our Scribbr review explains why.

Scribbr sells a one-off plagiarism report for students, priced by length with no subscription: $19.95 one-time for up to 7,499 words, $29.95 one-time up to 49,999 words and $39.95 one-time above that. According to third-party descriptions, it compares your text with web pages, academic journals and a store of previously submitted papers, and a paid check also unlocks its AI detector and proofreader.

Scribbr says documents aren't added to any public database, but its help pages and terms give different storage periods, so delete your file after you get the report. It has 4.2 out of 5 on Trustpilot (15,739 reviews, checked November 2026), though that rating covers all of Scribbr's services, not just the checker.