Don't Do It Yourself
Best Plagiarism Detection Tools

13 Best Plagiarism Checkers [Updated for 2024]

In the world of content creation, originality isn't just a virtue – it's a must.

That's why we, like your diligent teachers (and the ever-watchful eyes of Google), take checking for copied content seriously.

After all, authenticity is key to making a mark with your words. We've rolled up our sleeves and put the top plagiarism detection tools to the test, all so you don't have to.

Looking for the best ways to ensure your work is truly yours? You're in the right place.

Here are some of the best plagiarism AI detection tools we’ve used.

Best Free Plagiarism Checker

ContentatScale Logo

Content at Scale

  • Tied for highest accuracy in our test of all plagiarism detectors
  • Limited to checking 2,500 characters (~ 500 words)
  • Works with GPT-3

Learn More

Best Paid Plagiarism Checker

Originality AI Logo

Originality.ai

  • Tied for highest accuracy in our test of all plagiarism detectors
  • Dedicated plagiarism checker
  • No character limits on plagiarism checks
  • Works with GPT-3

Learn More

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Our Favorite Plagiarism Checkers

  • Content at Scale (5/5) – Best for AI writing and plagiarism checking
  • Copyscape (5/5) – Best PDF reader
  • Quetext (5/5) – Most detailed breakdown
  • Plagibot (4.5/5) – Best for a variety of documents
  • Copyleaks (4.5/5) – Best for enterprises
  • GPTZero (4.5/5) – Best for AI chat detection
  • Grammarly (4.5/5) – Best plugin tool
  • Scribbr (4.5/5) – Best for students
  • Unicheck (4.5/5) – Runner up for best for students
  • PlagScan (4.5/5) – Best source list provider
  • Originality.AI (4/5) – Best paid plagiarism detection
  • Turnitin (4/5) – Best for teachers/academia
  • Passed.AI (4/5) – Runner up for best for teachers

1. Content at Scale

Best for AI writing and plagiarism checking – 5.0/5 Rating

Content at Scale Logo Main

5 of 5 Stars

Content at Scale is best known for its stellar AI writing tool (seriously, it’s our favorite) but they also have an impressive new feature that allows users to check for both detectable AI content and plagiarism.

In mere seconds, this checker is able to tell you if there is any unoriginal content and breaks down how predictable each sentence is.

This tool is permanently bookmarked on our computers, so it’s safe to say it’s our top pick for plagiarism detection.

What Does It Detect

Content at Scale’s AI detector can detect content written by all versions of GPT including ChatGPT and GPT-4 and any AI text generator.

Other Useful Features

  • Done-for-you service
  • AI content writer
  • AI content detector
  • “Human” score
  • Detection scores for predictability, probability, and pattern
  • Highlights individual sentences for predictability

Pricing

Content at Scale’s AI and plagiarism detector is free.

 

Pros

  • Highly efficient in detecting plagiarism in large volumes of content
  • Offers scalability for content creators and businesses
  • Integrates AI to enhance content originality
  • User-friendly interface, easy to navigate
  • Provides detailed reports on content originality

Cons

  • May be more expensive than other tools
  • Could have a learning curve for new users
  • Limited features beyond plagiarism checking

Learn More


2. Copyscape

Best PDF Reader – 5.0/5 Rating

Copyscape Logo Main

5 of 5 Stars

Copyscape, a renowned plagiarism detection tool, utilizes Google as its search provider.

It conducts post-processing of the received search results to provide accurate and reliable plagiarism detection.

With its advanced algorithms, Copyscape efficiently scans the web, comparing your text against billions of web pages to detect any instances of plagiarism. Trusted by professionals and educators worldwide, it provides accurate and comprehensive results.

What Does It Detect

Copyscape is capable of identifying copied content from websites, online publications, blogs, and various online sources. It also allows users to determine if newly created material, whether acquired or generated through AI, plagiarizes text from other internet sources.

Other Useful Features

  • PDF and Word file uploads
  • Case tracking
  • An API
  • WordPress Integration
  • Copysentry automatically scans the web daily or weekly and emails you when new copies of your content are found
  • Free plagiarism warning banners for your website
  • A free tool to compare two web pages or articles

Pricing

  • Free version
  • Copyscape Premium– 3 cents per search (up to 200 words), plus 1 cent per extra 100 words
  • Standard Copysentry– Pages checked every week for $4.95/month for up to 10 pages and $0.25/month per additional page
  • Professional Copysentry– Pages are checked every day for $19.95/month for up to 10 pages and $1.00/month per additional page

 

Pros

  • Well-established reputation in the market
  • Simple and easy to use
  • Offers both free and premium versions
  • Good for web content and SEO professionals
  • Provides batch search features in premium version

Cons

  • Free version has limited features
  • Premium version can get expensive with extensive use
  • Sometimes misses more subtle forms of plagiarism

Learn More


3. Quetext

Most detailed breakdown – 5.0/5 Rating

Quetext Logo Main

5 of 5 Stars

Quetext simplifies the process of creating original content with its user-friendly platform.

The plagiarism checker thoroughly analyzes your text, detecting any instances of plagiarism, while also addressing other writing concerns and assisting in generating citations effortlessly.

Powered by advanced DeepSearch™ technology, Quetext utilizes contextual analysis, word placement, and intelligent algorithms to provide quick and accurate results.

Quetext also ensures the confidentiality of your work through industry-leading technology. With their three-part pledge, they are committed to delivering a trustworthy experience, empowering users to produce high-quality, authentic writing.

What Does It Detect

Quetext uses DeepSearch Technology to detect plagiarism from web pages, academic sources, news sources, and online textbooks.

Other Useful Features

  • ColorGrade™ feedback feature “highlights exact matches vs. near-exact or “fuzzy” matches with corresponding colors”
  • Contextual Analysis
  • Fuzzy Matching
  • Conditional Scoring
  • Spelling Checker
  • Grammar Checker (beta)
  • Chrome extension

Pricing

  • Free– includes Deep Search Plagiarism Checker (up to 500 words), website citation generator, and citation assistant
  • Premium Plans– start at $8.25/user/month- includes newly expanded citation generator, bulk file uploads, individual or small team plans, download & share originality reports, grammar check BETA, spell check, Chrome browser extension, 100,000 words/mo per user
  • Enterprise Plan– starts at $7.50/user/month- includes everything in premium for teams of 6 or more, includes 100,000 words/mo per user, additional users & word count available

 

Pros

  • Simple and easy to use
  • Offers deep search technology for thorough checks
  • Affordable pricing plans
  • Good for bloggers, educators, and students
  • Provides color-coded similarity reports

Cons

  • Limited features compared to some other tools
  • No free version is available
  • Occasionally misses some types of plagiarism

Learn More


4. Plagibot

Best for a Variety of Documents – 4.5/5 Rating

Plagibot Logo Main

4.5 of 5 Stars

The “plagiarism checker for everyone” Plagibot offers a free plan that supports a large variety of document types including .doc, .docx, .txt, and .rtf.

They’ve honed their NLP detection processes for over 10 years, creating a well-seasoned algorithm that catches most plagiarism and AI-written content.

It stays up-to-date with the latest news, constantly scraping the web and adding more than 60K new content pieces per hour to its database.

What Does It Detect

Plagibot’s site is vague on what all it can detect, but it is able to detect plagiarism from millions of sources in its database.

Other Useful Features

  • Easy-to-use AI
  • Free option
  • Variety of file formats supported

Pricing

The free tier has a limit of 2,000 words per month and after that, you will have to contact the company to inquire about pricing.

 

Pros

  • Quick and efficient in detecting plagiarism
  • Simple, easy-to-use interface
  • Affordable pricing structure
  • Good for bloggers and small businesses
  • Offers direct integration with WordPress

Cons

  • Limited features for advanced users
  • Smaller database compared to some competitors
  • Not ideal for academic or large-scale use

Learn More


5. CopyLeaks

Best for Enterprises – 4.5/5 Rating

Copyleaks Logo Main

4.5 of 5 Stars

CopyLeaks offers one of the most versatile and accurate AI and plagiarism detection tools available.

Claiming an over 99% accuracy rate, CopyLeaks is able to detect AI or plagiarized content in multiple languages including French, Spanish, German, and more.

Its uses vary widely, offering everything from helping teachers grade papers to giving your content an SEO boost while avoiding oppression from the Google algorithm and even in reviews to verify details.

What Does It Detect

CopyLeaks detects all iterations of the GPT model including GPT-4 and ChatGPT.

Other Useful Features

  • API and LMS integration
  • Free Google Chrome extension so you don’t have to visit the site to check for plagiarism
  • AI grader
  • Multiple languages offered

Pricing

Varies, but pricing starts at $10.99/month for 100 pages of content detection.

 

Pros

  • Uses advanced AI and machine learning for detection
  • Supports multiple file formats and languages
  • Cloud-based, accessible from anywhere
  • Good for academic and professional use
  • Integrates with several content management systems

Cons

  • More expensive than some alternatives
  • Can be complex for casual users
  • Sometimes returns false positives

Learn More


6. GPTZero

Best for AI Chat Detection – 4.5/5 Rating

GPTZero Logo Main

4.5 of 5 Stars

GPTZero takes a unique approach to AI and plagiarism detection.

This AI detector judges text on 2 characteristics: “perplexity” and “burstiness.” It gives content a perplexity score based on how predictable the text is (with lower numbers being more likely to be artificial and higher numbers denoting human writing) and burstiness based on creative variability (with higher scores meaning more human.)

Though a plagiarism detection tool originally built for educators, GPTZero has grown to become a favorite in the AI writing community, with over 1 million users to date.

What Does It Detect

GPTZero detects ChatGPT, GPT-3, GPT-2, LLaMA, and AI services based on those models.

Other Useful Features

  • API
  • Integration support
  • Free version
  • File batch uploads

Pricing

GPTZero has a free version and premium features available at custom pricing. Contact their team for more information.

 

Pros

  • Specifically designed to detect AI-generated content
  • Free to use, making it accessible for all users
  • Simple and straightforward interface
  • Quick analysis and results
  • Continuously updated to keep up with AI advancements

Cons

  • Limited to detecting AI-generated content only
  • Less effective for traditional plagiarism
  • Newer in the market with a smaller user base

Learn More


7. Grammarly

Best plugin tool – 4.5/5 Rating

Grammarly Logo Main

4.5 of 5 Stars

I can say with some degree of certainty that everyone on our team here at DDIY has the Grammarly extension on our computers. And one of the things it’s great at doing (among many others) is plagiarism detection.

With the premium subscription, they also have a tool that allows you to enter text right into its website and have it perform a free plagiarism scan.

While we wish the checker could be offered with the free version of Grammarly, the premium subscription isn’t too pricey and comes with other useful features.

Read our Grammarly Review.

What Does It Detect

Grammarly’s plagiarism checker can detect plagiarism from ProQuest’s academic databases and over 16 billion web pages, as well as plagiarized content in AI-created writing.

Other Useful Features

  • Citation checking
  • Real-time writing feedback
  • Spelling and grammar checker
  • Clarity-focused sentence rewrites
  • Tone adjustments
  • Word choice
  • Formality level
  • Fluency
  • Additional advanced suggestions

Pricing

  • Premium– $30/mo (billed monthly), $12/mo (billed annually)
  • Business– $15/month/seat (billed annually) 3 seat minimum, up to 10 seats; $14.50/month/seat (billed annually) 10-50 seats; $12/month/seat (billed annually) 50- 150+ seats.

 

Pros

  • Offers grammar and plagiarism checking in one tool
  • User-friendly interface
  • Widely used and trusted
  • Good for both academic and professional writing
  • Offers suggestions for writing improvements

Cons

  • Plagiarism checker is only available in the premium version
  • Can miss some types of plagiarism
  • More focused on grammar than in-depth plagiarism checking

Learn More


8. Scribbr

Best for students – 4.5/5 Rating

Scribbr Logo Main

4.5 of 5 Stars

With a focus on everything students and teachers need for academic writing, Scribbr is an excellent plagiarism checker.

Powered by Turnitin, Scribbr did the research and ranked as the top plagiarism checker of 2023, compared with big-name competitors like Grammarly and Copyleaks.

Not only is Scribbr able to detect plagiarism in both exact copies and heavily edited plagiarized texts, but it also provides a clear report with a percentage ranking of the detected plagiarism.

What Does It Detect

Scribbr detects plagiarism using Turnitin software from 99 billion web pages and 8 million publications in 20 languages.

Other Useful Features

  • APA editing
  • Academic editing
  • English proofreading
  • Spanish, French, or German
  • Online Proofreader
  • Citation generator

Pricing

After their free plan, Scribbr charges one-time fees per document based on document size.

  • Free plan
  • Small document– $19.95 for up to 7,499 words
  • Regular document– $29.95 for 7,500 – 49,999 words
  • Large document– $39.95 for 50,000+ words

 

Pros

  • Highly accurate for academic content
  • Uses a large database including scholarly articles and books
  • Provides detailed reports with useful feedback
  • Offers additional writing services
  • Trusted in the academic community

Cons

  • More expensive than some alternatives
  • Primarily focused on academic writing
  • No free version available

Learn More


9. Unicheck

Runner up for best for students – 4.5/5 Rating

Unicheck Logo Main

4.5 of 5 Stars

Unicheck is a plagiarism checker that prioritizes quality results over mere quantity.

With a winning combination of technological advancements and user-friendly design, Unicheck is committed to promoting authenticity rather than just highlighting similarities.

By using advanced algorithms, Unicheck goes beyond surface-level comparisons to ensure that the content is original. Unicheck provides a reliable tool to maintain academic integrity and originality, fostering a culture of authenticity whether you’re a student, educator, or writer.

What Does It Detect

Unicheck detects academic plagiarism from things like essay mills, academic cheating, letter substitution, translation from a different language, and fabricating sources.

Other Useful Features

  • Universal integration into your LMS
  • Ability to detect various text manipulations and display them side-by-side with the original text
  • 24/7 customer support through email, chat, and phone
  • Flexible similarity reports
  • Accessibility features
  • FERPA, COPPA, and GDPR compliant
  • Easily export reports as PDFs
  • Google Docs add-on

Pricing

  • Free
  • Personal Business– starting at $15/month

 

Pros

  • Fast and accurate plagiarism detection
  • User-friendly interface
  • Integrates well with several educational platforms
  • Supports bulk uploads
  • Good for both educational and professional use

Cons

  • More expensive for individual users
  • Limited features in the free version
  • Sometimes slow with large documents

Learn More


10. PlagScan

Best source list provider – 4.5/5 Rating

Plagscan Logo Main

4.5 of 5 Stars

With just a few clicks, PlagScan's Plagiarism Detection software enables you to verify the authenticity of any text. It works effectively with all popular file formats, making the plagiarism-checking process hassle-free.

The PlagScan Report is customizable to suit each user’s individual requirements, whether they prefer a printable PDF-file or an interactive browser report for collaborative purposes.

At PlagScan, they also prioritize privacy and legal compliance, guaranteeing that any and all uploaded documents remain confidential and are never shared with unauthorized parties.

What Does It Detect

PlagScan detects plagiarism from the WorldWide Web, the user’s own uploaded repository, a network of millions of articles from thousands of different scientific and academic journals, and documents from other PlagScan users if you choose to opt-in to the Plagiarism Prevention Pool.

Other Useful Features

  • Source list
  • Plagiarism Prevention Pool
  • Color-coded reporting system shows differences between direct matches with sources, potentially modified text, and information with cited sources.
  • Side-by-side comparison
  • Easy upload and download feature

Pricing

  • 6,000 words/24 pages– $5.99
  • 17,500 words/70 pages– $12.99
  • 40,000 words/160 pages– $24.99
  • 100,000 words/400 pages– $49.99

 

Pros

  • Offers a thorough plagiarism checking process
  • Suitable for academic, professional, and personal use
  • Provides a detailed plagiarism report
  • User-friendly interface
  • Offers a trial period to test the service

Cons

  • Can be more expensive than other tools
  • Sometimes slow in processing documents
  • Interface is less modern compared to competitors

Learn More


11. Originality.AI

Best paid plagiarism detection – 4.0/5 Rating

Originality Ai Logo Main

4 of 5 Stars

Originality.AI’s detector allows site owners to gain insight into how human-like their content is and see how original the content itself is.

By doing both at the same time, site owners and content creators can save time and money and mitigate the risk of Google detecting any machine-created content.

This detector was able to detect plagiarism and AI content with 96% accuracy, making it one of the most accurate detectors available.

What Does It Detect

Originality.AI’s detector can detect all versions of GPT including Chat GPT, GPT-2, GPT-3, and GPT-4, Bard, and Quillbot.

Other Useful Features

  • Team management tools
  • Full site scan (coming soon)
  • Auto-billing
  • Scan history by user

Pricing

Originality.AI costs $0.01 per 100 words per scan.

 

Pros

  • Specializes in detecting AI-generated content
  • User-friendly and efficient
  • Offers bulk checking options
  • Integrates well with other content management tools
  • Provides detailed insights into content originality

Cons

  • Relatively new in the market, less proven track record
  • May miss some nuances in human-written content
  • Limited language support compared to others

Learn More


12. Turnitin

Best for teachers/academia – 4.0/5 Rating

Turn It In Logo Main

4 of 5 Stars

Turnitin has been trusted by teachers and professors alike for what feels like forever, making it worthy of its high placement on our plagiarism detector list.

Turnitin is designed to scan a wide array of sources including its “archive of internet documents, internet data, a repository of previously submitted papers, and a subscription repository of periodicals, journals, and publications” that may be in the student’s writing. It has also evolved to detect AI content as well.

It’s also used to provide researchers with feedback and insights on their material.

What Does It Detect

Turnitin can detect anything that has been copied from an existing source as well as all GPT iterations including ChatGPT.

Other Useful Features

  • AI writing detection
  • Gradescope delivers and grades papers from anywhere in the world
  • Feedback studio to give students feedback
  • Examsoft for instant data insights from secure online exams

Pricing

Pricing for Turnitin varies widely based on what custom solutions you use, so you’ll need to contact a sales representative for accurate pricing.

 

Pros

  • Widely recognized and trusted in academic circles
  • Extensive database including academic papers
  • Detailed similarity reports
  • Helps improve student writing and research skills
  • Integrates with many educational platforms

Cons

  • More expensive for individual users
  • Sometimes flags common phrases as plagiarism
  • Reports can be complex for beginners

Learn More


13. Passed.AI

Runner up for Best for Teachers – 4.0/5 Rating

PassedAI Logo

4 of 5 Stars

Passed.AI uses Originality.AI’s high-quality detection technology, so you can rest assured that any AI content will be easily identifiable. But they take it a step further.

Passed.Ai has additional tools, including a Replay Tool, History Report, and Document Audit, that make it the perfect solution for advanced plagiarism detection.

What Does It Detect

Passed.AI is able to detect content created by all major NLP models, including every iteration of GPT as well as ChatGPT.

Other Useful Features

  • Easily submit documents using Google Docs
  • Document History Audit that lets teachers “watch” a student write the text
  • REST API for easy integration
  • Priced with teachers in mind

Pricing

  • Standard plan– $9.99/month, free 14-day trial, Unlimited scans, 200 free credits per month, Access to: Document Audit, History Report, and Replay Tool. Use credits for AI Detection and Plagiarism.
  • $0.1 per credit (1 credit scans up to 200 words)
  • Institution plan– flexible pricing, contact them for more information.

 

Pros

  • AI-driven, offering advanced plagiarism detection
  • Efficient for both academic and professional use
  • User-friendly interface
  • Offers detailed similarity reports
  • Good for checking a wide range of document types

Cons

  • Relatively new, less established reputation
  • May have limitations in database compared to older services
  • Fewer features than some competitors

Learn More


How We Chose Our Favorites (Ranking Metrics)

We looked at a few things when choosing our list of favorites.

Accuracy and Reliability

The whole point of plagiarism checkers is accuracy. We checked to make sure each of these plagiarism checkers was accurate and reliable, producing accurate readings on whether or not content was plagiarized.

Database Coverage

The more sources a plagiarism checker has to pull from, the more comprehensive the evaluation can be.

Ease of Use

A plagiarism checker is useless if you can’t figure out how to work the interface. All of these have an intuitive interface design that allows you to check content easily and quickly.

Report Detail & Quality

A good plagiarism checker will provide as much detail and information as possible. Many of the ones on this list offer useful features that highlight specific plagiarized content and give ratings for how likely each section is plagiarized.

Why Should You Use AI and Plagiarism Detection Tools?

Why Use Plagiarism Detectors

You should use AI and plagiarism detection tools to make sure that the content you distribute is free from plagiarism and undetectable.

Folks in academia, especially teachers, need to make sure students’ work is original, and plagiarism checkers are the only way to do that.

Google’s algorithm punishes AI content by pushing it further down in search results. If you use an AI writer and then publish that content without checking it first, you could end up at the bottom of the list. AI detection tools can let you know how detectable your content is and what changes need to be made for it to fly under Google’s radar.

How to Choose the Right Plagiarism Detection Tools

How to Choose Plagiarism Detection Tool

To choose the right plagiarism detection tools, first, consider what you’re using them for. Are you a teacher who needs to check dozens of papers? Are you a digital marketer who needs to check AI-written content for SEO purposes? Or are you a researcher who wants to check your work before publishing?

Next, consider your budget. There are many free AI detectors out there that will get the job done, but some offer more accuracy and extra features at a price.

Lastly, do your research (this article is a good start!) Make sure your plagiarism detection tool is accurate and trusted by others.

Frequently Asked Questions

What are the best free plagiarism and AI writing detectors?

The best free tools for detecting plagiarism and AI-generated content are Content at Scale for plagiarism detection and HuggingFace for AI writing detection.

Content at Scale offers a robust solution for checking the originality of text against a wide array of online sources, making it ideal for anyone needing to ensure their work is plagiarism-free.

On the other hand, HuggingFace has developed a specialized detector to identify writings produced by AI, helping to distinguish between human and machine-created content.

Both tools are accessible without cost and are highly regarded for their effectiveness and ease of use.

What is the best paid plagiarism and AI writing detector?

Originality.AI is currently one of the top paid solutions for detecting both plagiarism and AI-generated content.

It is designed for anyone who needs a reliable method to verify the uniqueness and authenticity of written material, including publishers, academic institutions, and content agencies.

This tool combines the detection of plagiarized text with the ability to identify content that may have been created by AI writing tools, offering a dual-purpose utility.

With a user-friendly interface and comprehensive scanning capabilities, Originality.AI provides a valuable service for users willing to invest in a premium detection tool.

Should I use detection tools?

Definitely, using detection tools is a prudent step before publishing any content, especially when it's AI-generated, to ensure originality and to avoid potential copyright infringement issues.

For educators, these tools are essential in maintaining academic integrity by helping to detect plagiarism in student papers. They serve as a check against unintentional plagiarism and as a deterrent against the misuse of AI writing assistants.

By using detection tools, you can uphold the quality and credibility of your content or the academic work you are assessing.

Are plagiarism detectors accurate?

Plagiarism detectors are generally accurate in identifying exact matches or near-identical content to the sources they have in their databases.

However, the accuracy can vary based on several factors, including the size and comprehensiveness of the database, the sophistication of the detection algorithm, and the nature of the content being checked.

While no tool can guarantee 100% accuracy due to the vastness of existing and new content online, many advanced plagiarism detectors are continually updating their databases and improving their algorithms to provide high levels of accuracy.

It's important to review the results and consider the context of any matches found, as some may be common phrases or false positives.