I Tested The Best Free Plagiarism and AI Content-Checking Sites

Plagiarism is an age-old problem. Artificial intelligence-generated content is a very new problem. Yet these two practices—one ancient and one modem—are linked by their ability to replace true learning with copy-and-paste.

The word plagiarism, derived from the Latin plagiarius (“kidnapper”), dates back to 17th-century English. Much earlier than that, in the first century, the Roman poet Martial used “plagiarius” to castigate another poet whom he accused of appropriating his words.

In our modern world, however, the ability of students to find and copy others’ work is greater than ever before. While there are a number of in-depth and effective paid solutions that allow educators to verify the originality of student work, there are only a few free solutions that are worth trying.

Sites that characterized trial texts as substantially or highly plagiarized or AI-generated passed my testing. Sites that didn’t recognize texts as such were deemed unreliable and therefore excluded. Interestingly, six sites which had passed near-identical plagiarism testing three years ago failed the most recent testing and have been excluded.

Read on for the best free online plagiarism and AI-generated content checkers. Interested in non-tech methods of detection? Check out T&L contributor Erik Ofgang’s article 10 Ways to Detect AI Writing Without Technology.

Best Free Plagiarism and AI Content-Checking Sites

Grammarly
Grammarly’s free plagiarism and artificial intelligence detector tools allow users to simply paste text or upload files to be scanned for plagiarized or AI-generated text. No account is needed for the first scan. After that, users can quickly create a free account via Google, Apple, or email to continue scanning. In my testing, Grammarly correctly identified plagiarism in all three texts, reporting each time in this way: “We have found significant plagiarism in your text.” While the free version does not provide a line-by-line plagiarism analysis, it is nevertheless a very good choice for a free detector, especially considering the generous 1500-word limit. Grammarly’s AI detector delivered a perfect result, correctly identifying all three AI-generated texts as 100% AI.

Quetext
With a clean, well-designed interface, it’s a pleasure to use Quetext. After the first free search, you’ll need to create a free account. Current testing results were near-perfect, with 98%, 100%, and 100% for plagiarized texts, and 100% for all AI-generated texts. Unlike many other plagiarism sites, Quetext makes it easy to compare the free and pro offerings — free accounts allow 2,500 words monthly, while the paid Pro account allows 100,000 words, plus deeper search capability. The site usefully displays the number of words remaining in your word count. An excellent, user-friendly choice.

Dupli Checker
Dupli Checker furnishes a hassle-free plagiarism- and AI-content-checking experience. With no account needed, users can check for plagiarism and AI-generated content once daily. Offering a robust 2000-word limit, the site identified the three plagiarized texts as 100%, 100%, and 92% plagiarized, and the AI-generated texts as 100%, 89%, and 82% AI content. Note that retained cookies from Dupli Checker may interfere with results, so it’s best to clear cookies after each session. To access unlimited plagiarism checks and additional features such as downloading Word or PDF plagiarism reports, create a free account. Dupli Checker also provides a set of free, entertaining, and useful text and image tools such as the reverse text generator, favicon generator, and MD5 generator.

Plagiarism Detector
Easily check for plagiarism without creating an account, then download the pdf report file at no charge. The site accommodates multiple languages, while allowing unlimited free checks of text up to 1,000 words. In the latest testing, Plagiarism Detector characterized plagiarized texts as 100%, 100% and 92% plagiarized, while its AI content detector performed well, reporting 100%, 78%, and 82%. Flexible premium accounts are available on a weekly, month or yearly basis.