Best Plagiarism Checkers Compared

The best plagiarism checker should be able to detect plagiarism the most accurately, even if the original phrasing has been altered. The tool should also provide a clear, comprehensive plagiarism report.

To identify which plagiarism checker is best, we conducted in-depth research comparing the performance of 10 checkers. We uploaded plagiarized texts that were either directly copied and pasted or edited to varying degrees. In total, we used 140 sources to construct our test documents.

Conclusion
Our in-depth research shows that Scribbr’s free plagiarism checker is the best plagiarism checker on the market. It is able to detect plagiarism in both exact copies and heavily edited plagiarized texts, and it provides a clear report.

Overview of total scores per plagiarism checker, based on the amount of detected plagiarism:

Plagiarism checker Overall score
1. Scribbr (in partnership with Turnitin) 4.2 
2. Plagaware 2.9 
3. Quetext 2.5 
4. Viper 2.2 
5. Grammarly 2.0 
6. Plagiarism Detector 2.0 
7. Copyleaks 1.7 
8. Smodin 1.6 
9. Compilatio 1.5 
10. Writer 1.4 

Continue reading: Best Plagiarism Checkers Compared

Best AI Detector | Free & Premium Tools Tested

AI detectors are tools designed to detect when a text was generated by an AI writing tool like ChatGPT. AI content may look convincingly human in some cases, but these tools aim to provide a way of checking for it. We’ve investigated just how accurate they really are.

To do so, we used a selection of testing texts including fully ChatGPT-generated texts, mixed AI-and-human texts, fully human texts, and texts modified by paraphrasing tools. We ran all these texts through 12 different AI detectors to see how accurately each tool labeled them.

Our research indicates that if you’re willing to pay, the most accurate AI detector available right now is Scribbr’s premium AI Detector, which identified 84% of our texts correctly. If you don’t want to pay, the best choices are QuillBot’s and Scribbr’s free AI Detectors: they are totally free and both scored 78% accuracy, a tie for the second highest score among all tools.

Best AI detectors in 2024
Tool Accuracy False positives Free? Star rating
1. Scribbr (premium) 84% 0 4.2
2. QuillBot 78% 0 3.9
3. Scribbr (free) 78% 0 3.9
4. Originality.AI 76% 1 3.7
5. Sapling 68% 0 3.4
6. CopyLeaks 66% 0 3.3
7. ZeroGPT 64% 1 3.1
8. GPT-2 Output Detector 58% 0 2.9
9. CrossPlag 58% 0 2.9
10. GPTZero 52% 1 2.5
11. Writer 38% 0 1.9
12. AI Text Classifier (OpenAI) 38% 1 1.8
Note
To understand where these scores come from, you can read more about our methodology below. You may also be interested in our comparison of the best plagiarism checkers.

Continue reading: Best AI Detector | Free & Premium Tools Tested

Best Paraphrasing Tool | Free & Premium Tools Compared

Paraphrasing means rewording something—expressing the same idea in different words. Paraphrasing tools (or paraphrasers) are AI-powered online tools that can automatically rewrite your text for you. Students often use them to improve their writing and provide inspiration—making their text more formal, more fluent, or more concise.

But which online paraphrasers are really reliable at producing correct and readable English? To find out, we tested seven of the most popular free tools—and their premium versions when available.

We wrote three short sample texts to test their ability to improve text that was long-winded, grammatically incorrect, or disjointed. We ran these texts through all the different tools and assessed the fluency and accuracy of the output. We also took the user-friendliness of the tools into consideration.

The results show that the premium versions of QuillBot and Wordtune are the best tools out there, each excelling in different ways. If you’re looking for a free tool, QuillBot and Paraphrase Tool are the strongest options.

Paraphrasing tool Score
1. QuillBot (Premium) 4.0
2. Wordtune (Premium) 4.0 
3. QuillBot (Free) 3.5
4. Paraphrase Tool (Free) 3.5
5. Paraphrase Tool (Premium) 3.0
6. Wordtune (Free) 3.0
7. Rephrase (Free) 2.5
8. Paraphraser.io (Free) 2.0
9. Rephrase (Premium) 2.0
10. Paraphraser.io (Premium) 1.5
11. SpinBot (Free) 0.5
12. Pre Post SEO (Free) 0.5
13. Pre Post SEO (Premium) 0.5
Disclaimer
Scribbr is affiliated with QuillBot through our parent company, Learneo. However, we took care to compare all tools fairly, without giving QuillBot any advantages.

You can read about our methodology below.

Continue reading: Best Paraphrasing Tool | Free & Premium Tools Compared

Best Free Plagiarism Checkers

To find the best free plagiarism checker, we extensively tested and reviewed all popular tools to answer questions like, “How much plagiarism can they detect?” and “Are they actually free?”

Conclusion
Across several test documents featuring 140 sample texts, the average plagiarism percentage detected is only 42% for entirely free tools and 47% for freemium tools. With a detection rate of 83%, Scribbr’s free plagiarism checker proved to be the most reliable.
Best free plagiarism checkers
Plagiarism checker Overall score 100% free? Limitations
1. Scribbr 4.2  No full report in the free version
2. Quetext 2.5 Trial of 1 scan (500 words)
3. DupliChecker 2.2 1,000 words / check
4. Small SEO Tools 2.2 1,000 words / check
5. Pre Post SEO 2.1 Llimits not clearly explained
6. Grammarly 2.0 “Free” version gives no information
7. Plagiarism Detector 2.0 1,000 words / check
8. Check-plagiarism.com 2.0 Limits not clearly explained
9. Search Engine Reports 1.9 1,000 words / check
10. Plagiarismchecker.co 1.5 5 free checks; 800 words / check

Continue reading: Best Free Plagiarism Checkers

How to Write a Paper with ChatGPT | Tips & Examples

A good research paper demonstrates your academic writing skills and knowledge of your chosen topic.

Your research paper should be based on in-depth independent research. However, generative AI tools like ChatGPT can be effectively used throughout the research process to:

Note
Universities and other institutions are still developing their stances on how AI writing tools may be used. Always follow your institution’s guidelines over any suggestions you read online. Check out our guide to current university policies on AI writing for more information.

Continue reading: How to Write a Paper with ChatGPT | Tips & Examples

How to Write a Conclusion Using ChatGPT | Tips & Examples

A good conclusion is a key part of any essay or dissertation. It summarizes your main arguments and highlights the implications of your research.

Your conclusion should accurately reflect your own research and findings. However, AI tools like ChatGPT can be be used during the writing process to:

  • Develop an outline for your conclusion
  • Summarize text
  • Paraphrase text
  • Provide feedback
Note
Universities and other institutions are still developing their stances on how ChatGPT and similar tools may be used. Always follow your institution’s guidelines over any suggestions you read online. Check out our guide to current university policies on AI writing for more information.

Continue reading: How to Write a Conclusion Using ChatGPT | Tips & Examples

How to Write an Introduction Using ChatGPT | Tips & Examples

A good introduction is essential to any essay or dissertation. It sets up your argument and clearly indicates the scope and content of your writing.

Your introduction should be an authentic representation of your own ideas and research. However, AI tools like ChatGPT can be effectively used during the writing process to:

Note
Universities and other institutions are still developing their stances on how ChatGPT and similar tools may be used. Always follow your institution’s guidelines over any suggestions you read online. Check out our guide to current university policies on AI writing for more information.

Continue reading: How to Write an Introduction Using ChatGPT | Tips & Examples

Using ChatGPT to Write a College Essay | Tips & Examples

A good college essay helps to distinguish your application from those of other candidates. It conveys your experiences, values, and character traits and indicates why you would make a good addition to the university you’re applying to.

Your college essay should be your own work. However, AI tools like ChatGPT may be helpful during the preparation and revision stages of your writing.

You can also use the essay checker, so you don’t have to revise your writing yourself.

You can use these tools to:

  1. Brainstorm essay ideas
  2. Develop an outline
  3. Generate feedback

Continue reading: Using ChatGPT to Write a College Essay | Tips & Examples

How to Write an Essay with ChatGPT | Tips & Examples

Passing off AI-generated text as your own work is widely considered plagiarism. However, when used correctly, AI tools like ChatGPT can legitimately help guide your writing process.

These tools are especially helpful in the preparation and revision stages of your essay writing.

You can use ChatGPT to:

  1. Write a research question
  2. Develop an outline
  3. Find relevant source information
  4. Summarize or paraphrase text
  5. Get feedback
Note
Universities and other institutions are still developing their stances on how AI writing tools may be used. Always follow your institution’s guidelines over any suggestions you read online. Check out our guide to current university policies on AI writing for more information.

Continue reading: How to Write an Essay with ChatGPT | Tips & Examples

Comparing Plagiarism Checker Tools | Methods & Results

In seeking to find the best plagiarism checker tool on the market in 2023, we conducted an experiment comparing the performance of 10 checkers. We also carried out a separate experiment comparing 10 free plagiarism checkers. There was some overlap between the two experiments in terms of the tools covered.

We focused on a series of factors in our analysis. For each tool, we analyzed the amount of plagiarism it was able to detect, the quality of matches, and its usability and trustworthiness.

This article describes our research process, explaining how we arrived at our findings.

We discuss:

  • Which plagiarism checkers we selected
  • How we prepared test documents
  • How we analyzed quantitative results
  • How we selected criteria for qualitative analysis

Continue reading: Comparing Plagiarism Checker Tools | Methods & Results