Grammarly Plagiarism Checker Review

Being able to check for plagiarism while you write is a must-have in our modern day and age. Not only does it help boost the quality of your paper or research, but it also improves your credibility as a content professional in your chosen field or niche. When your work is original, you also sidestep

Being able to check for plagiarism while you write is a must-have in our modern day and age. Not only does it help boost the quality of your paper or research, but it also improves your credibility as a content professional in your chosen field or niche. When your work is original, you also sidestep any legal pitfalls that could cost you legally, financially or both.

Numerous online tools and platforms have sprung up to help with the latter, Grammarly being one of the most well-known. In addition to checking for grammatical or spelling errors, Grammarly makes real-time suggestions that can also help users improve the style of their writing.

As a comprehensive writing tool, it also includes a built-in plagiarism checker, comparing your text to billions of academic research papers, web pages, and more to determine if the information has been copied from elsewhere. In this detailed Grammarly plagiarism checker review, we put it to the test to determine how well Grammarly’s plagiarism checker really works, particularly with texts written by AI writers and platforms like ChatGPT.

But before we get into the performance review, let’s take a close look at what Grammarly Plagiarism checker has to offer, how it works, and how it compares to other plagiarism checkers on the market, including Originality.AI's AI Detector.

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What is Grammarly Plagiarism Checker?

Grammarly Plagiarism Checker is a built-in feature of the Grammarly online platform, which helps users improve their writing by identifying spelling and grammar errors and highlighting alternative options as well as improved style suggestions. Grammarly itself was released in 2009 and has only continued to improve through its use of automated suggestions and AI-powered enhancements.

How Does Grammarly Plagiarism Checker Work?

Grammarly’s Plagiarism Checker is designed to check for writing issues as well as note instances of plagiarism it may find as it does so. It scans over 15 billion web pages as well as ProQuest databases, which are themselves a collection of databases for a variety of journals, newspapers, academic papers, magazines, and more.

Why Should You Use Grammarly Plagiarism Checker?

The Grammarly Plagiarism Checker can be incredibly helpful if you’re already well-versed in using Grammarly to improve your writing style and tone. The addition of the Plagiarism Checker is available at no extra charge for Premium and Business accounts and can be a helpful way for content professionals to keep their writing geared toward a specific tone, delivery, style and more.

What are Some of the Grammarly Plagiarism Checker’s Features?

The Grammarly Plagiarism Checker is only available in Premium and Business-level Grammarly accounts. Like any basic plagiarism checker? It looks at specific sentences of lines of text and flags those which match other documents or websites. It also calculates an “originality score” and gives you feedback on ways that you can improve your writing. At all times, what you write remains private on the platform.

How Does Grammarly Plagiarism Checker Compare to Other Plagiarism Checkers?

Many plagiarism checkers work simply by looking for matching strings of text in a given work. Grammarly does this but also goes much farther than the average plagiarism checker by also checking across ProQuest, which is a collection of databases of magazines, academic research, and other documents beyond websites.

Grammarly’s plagiarism checker is often compared to Turnitin, an academic plagiarism checker used by numerous colleges and universities. Despite its expansive database, Grammarly has fewer sources upon which to draw from than Turnitin, so it won’t detect as many “hits” for an identical piece of content as Turnitin does. This is why if you happen to run a piece through both services, you could get substantially different results.

How the Grammarly Plagiarism Checker’s Algorithm Works

From the moment you click the Plagiarism button in Grammarly, the service goes to work, comparing your text to billions of web pages as well as magazines and research papers across various ProQuest databases. If there’s a match to any of these, you’ll receive a plagiarism alert.  

This alert will not only show you the offending text but also flag any text that may need a citation and show you the source material it pulled the quote or other data from.

How to Use Grammarly Plagiarism Checker

Using Grammarly’s Plagiarism Checker is simple and straightforward. To check for plagiarism, simply click the plagiarism button in the upper right corner of the page. Grammarly then takes a few moments to scan for any matches. When the scan is done, it will show you what percentage of your document’s content matches other content online or in ProQuest databases.

How to Get the Most Out of the Grammarly Plagiarism Checker

Overall, Grammarly’s Plagiarism Checker is a great tool to ensure your work is as original as possible. In order to get the most out of it, we recommend the following steps:

Check for Plagiarism as Your Final Step

Ideally, you should write first and check for plagiarism as one of your last steps. This allows you to focus on your writing without constantly being worried about whether or not you’re borrowing too much from someone else’s work. The platform will let you know if that’s the case, so concentrate on your writing and let the system handle the plagiarism red flags.

Use it to Check for Accidental Plagiarism

Sometimes you can inadvertently use someone else’s words or fail to properly cite a quote or other data. These cases of accidental, unintentional plagiarism are more common than you might think and Grammarly’s Plagiarism Checker can help you spot them. It may even help you spot areas where you’ve plagiarized from yourself!

Make Your Sources More Diverse

Don’t forget that Grammarly pulls from many different databases and sources, so the more diverse you can make your sources, the more accurate the results will be. This means you can freely use supporting content from magazines, websites, academic papers and much more without worrying as to whether or not Grammarly will find them. It has an extensive database of databases to draw upon which includes billions of potential sources.

Use the Premium Version

Grammarly’s free version offers a number of features, however, the Plagiarism Checker is not among them, so be sure to use the premium version if you want to be able to accurately check for plagiarism in your documents.

Step-by-Step Guide on How to Use Grammarly Plagiarism Checker

  • If you haven’t already, the first step to using Grammarly’s plagiarism checker is to sign up for a premium Grammarly account.
  • Next, you can choose to either install the Grammarly extension on your preferred browser (Chrome, Safari, Edge or Firefox) or the web-based editor or both.
  • Write directly in the editor or copy and paste your text directly into Grammarly.
  • Click the Plagiarism button and wait for the process to complete.
  • Review the generated plagiarism report. Note any areas where the platform has highlighted as potentially plagiarized. You can review them individually and decide for yourself if you need to make changes or not.
  • Don’t forget to check out the Plagiarism Checker’s own suggestions for improving your writing. These suggestions are designed to make your writing sound more authentic and more “your own”. and can help make your writing even better.

Common Issues and Troubleshooting

Although Grammarly’s Plagiarism Checker is very reliable, there are a few common issues that users have reported, including:

False positives: Sometimes, Grammarly can mistakenly note text as unoriginal when it is in fact original. This is more likely to happen if you’re using certain expressions that commonly appear in other databases. You can decide to change your writing on a case-by-case basis for each of the items that Grammarly has found so you can opt to edit it or not.

Slow scanning: Some users remark that Grammarly’s plagiarism check can be slow. If your text is quite long or you have a lower-quality internet connection, the scan can take even longer. If you continue to experience issues, try a more stable connection or chunks of text at a time.

Technical issues: Grammarly is a Software as a Service and like any such platform, it’s not immune to the occasional technical glitches or hiccups from time to time. If this continues to happen, try logging out, clearing your browser cookies, and logging in again. You may need to restart your computer to complete the process.

Limited number of sources: Although a database of databases from many different magazines, research papers, and articles plus billions of web pages sounds like a lot, it’s actually quite limited when compared to the vast repository of information out there. If you’re worried about plagiarism, you may want to use an additional tool to scan your work beyond what Grammarly Plagiarism Checker offers.

Premium account needed: As the free version of Grammarly doesn’t offer a plagiarism checker, you’ll need to upgrade to a Premium account or higher to take advantage of this feature.

Advantages of using Grammarly Plagiarism Checker

Using Grammarly’s Plagiarism Checker offers you a number of advantages to help you sidestep instances of plagiarism. The system itself is built on advanced algorithms that root out many of the most common plagiarism issues beyond simple text matching. By drawing upon multiple sources, you can trust that your work is as original and authentic as possible.

In addition, the plagiarism checker is easy to use. You don’t need to have separate windows or tabs open to check your work. Everything is built-in to the Grammarly editor. Moreover, Grammarly doesn’t just check for plagiarism, but also offers helpful suggestions in terms of proper citation and other recommendations to make your writing stronger.

Limitations of the Tool

For all of its benefits, there are some drawbacks to the Grammarly Plagiarism Checker. Most importantly, it only works with text. It cannot check for the plagiarism of images, audio, videos, or any other type of file. In addition, its database only checks online sources. It cannot check for any print or offline services. Even then, it may not highlight all potential instances of plagiarism after a scan.

Keep in mind that the tool is also limited to Premium or higher account users and it is limited to English-only searches. If you are quoting or citing something in a language other than English, the plagiarism checker will not flag this.

Alternatives to Other Plagiarism Checkers on the Market

Of course, this wouldn’t be a complete review if we didn’t compare Grammarly to other plagiarism checkers on the market.


Turnitin is generally used in colleges and universities whereas Grammarly Plagiarism Checker is used by students, professors, content creators and writers as a more general tool. As such, Turnitin focuses more on academic papers and databases. It’s also generally baked into LMS (learning management systems) used on campuses and schools rather than a standalone platform like Grammarly.


As a purely web-based system, Copyscape is limited to checking existing web content and doesn’t check academic journals, research papers, or any other type of content. In order to use Copyscape, you must upload your content to their site. Copyscape is an entirely paid service and given its general scope, is more limited than Grammarly’s Plagiarism Checker.


Originality’s sole focus is checking for plagiarism and originality within a given document – that is, to see if it was written by an AI versus a human. Many AI-based services use content from multiple sources to deliver their “answers”, so Originality.AI checks your content against what can reasonably be produced from an AI. Both platforms are well-known for their high levels of accuracy.

Originality.AI: How it Works

Originality.AI has been built from the ground up to do one thing and do it exceedingly well: check for plagiarism among AI-based writing tools. To do this, it leverages AI as a plagiarism checker rather than a writing source and scans academic journals, databases, and other repositories for content that could sound machine-written. Like Grammarly, it highlights any instances where a copy could be viewed as AI-written so that you can make changes on a case-by-case basis.

How Originality.AI Compares to Grammarly Plagiarism Checker

Grammarly Plagiarism Checker is designed to not only check for plagiarism but also offer writing suggestions and recommendations. Conversely, Originality.AI is designed to check for plagiarism as well as AI-written content. It does not offer critiques or suggestions on how to better phrase your writing or improve your tone or style. It works to check the authenticity of your work when compared to tools like ChatGPT and other AI writing services.

How Originality.AI’s Algorithm Works

Originality.AI leverages machine learning and AI systems to determine how unique your content is when compared with other academic and professional databases. Its highly-sophisticated algorithm “preprocesses” your text to strip out any formatting so that it can be purely analyzed. From there, it creates a type of unique “fingerprint” that lets it compare sentences to the content in its databases.

Rather than checking to see whether a string of text matches something else in a given document, it compares the fingerprints of your document with the fingerprints of other, similar documents in the database. This is known as Locality-Sensitive Hashing or LSH. It greatly speeds up the time to conduct a check and allows the system to more thoroughly search existing content.

If a match is found, Originality.AI notes it and the source and lets the user decide how they wish to resolve the issue, either by editing their work and scanning again or proceeding without changes.

The Bottom Line: Should You Use Grammarly’s Plagiarism Checker?

If you want suggestions and recommendations on improving your writing to be more grammatically succinct and stylish (in addition to being plagiarism-free), Grammarly’s Plagiarism Checker can be a valuable tool as you work to become a more well-versed writer. However, keep in mind that although Grammarly’s Plagiarism Checker does give you an originality score, it in no way offers the depth and breadth of Originality.AI in terms of checking for AI-produced content or content that matches similar items in other databases in terms of its tone or expression the way Originality.AI’s fingerprinting system does.

Ideally, you’ll want to use both platforms to ensure that your writing meets all grammatical and spelling standards as well as citation standards for the work you’re looking to present. This ensures that each piece you produce goes full circle with regard to being original and authentic, as well as structurally sound and interesting to read.

Sherice Jacob

Plagiarism Expert Sherice Jacob brings over 20 years of experience to digital marketing as a copywriter and content creator. With a finger on the pulse of AI and its developments, she works extensively with to help businesses and publishers get the best returns from their Content.

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