14 Best Online Plagiarism Checker Tools for Writers in 2021

One issue that most Internet marketers encounter every day is plagiarism.

Whether your business is related to SEO or not, plagiarization is something that you should pay close attention to.

Don’t want to read? Click here to jump to the Plagiarism checker tools list.

Why plagiarism matters so much for your business?

According to Vocabulary.com, they explain the meaning of “plagiarism” like this.

When you rip off someone else’s ideas or work and pretend it’s your own, that’s plagiarism.Vocabulary.com

Read that citation again carefully.

When someone steals your content and pretends it is their own work, it is known as plagiarism or piracy.

Why does plagiarisation matter to your business so much?

Even you are a teacher, college student, university professor, freelance writer, data entry worker, or offline article writer, plagiarism matters to your business directly.

For example, let’s say you’ve got an order from a client to write an original article about “The Truth about Abs…”. He is going to publish that article on their blog.

As you might know, the weight loss & fitness industry is way too competitive. So, there are more chances to get your article being plagiarized?

What does that mean “getting your article plagiarized”?

Yes, plagiarism could be made unintentionally.

The more common (and widespread) and lengthier your content is, there are more chances to add similar sentences to your article.

That ends up with having more similarities.

Once your article’s purity or originality is lower down than the recommended plagiarism percentage, you might have been labeled as a “content thief.”

Yes, that’s the harsh truth about Plagiarism…Ok, Chamal…. Nice words… I am actually convinced about plagiarism issues.

How do I get rid of plagiarism? Is there a better way to check plagiarism online?

Yes, luckily for you, there are a few plagiarism checkers.

Some are free plagiarism checker tools that work efficiently online, while others are plagiarism software that works on your PC, laptop, and even your mobile device.

As a blogger and SEO guy, I have used a few online plagiarism checker tools. They can detect plagiarism quickly and give the location of other copied content.

While very few of those plagiarism detectors can compare each document/webpages/essay.

That means you can find similarities between the two documents. It is beneficial in most scenarios……Without further ado, I will list my best plagiarism checker tools that I have used and found on the Internet. Feel free to use ANY of the below anti-plagiarism checker tools.

Note: There’s no ANY descending order of the list. So, you can always try ANY plagiarism detection tool and find the best one that suits your needs.

For example, if you’re a school teacher, student, or even an average person, you may use a free plagiarism checker. But, if you’re an article writer (doing writing as your professional job) and especially an SEO guy, then you should look for a premium plagiarism checker.

One last word, I promise that if you know ANY other tool you love using for every project to check plagiarism, share it in the comment form below. I will check it out, and if it’s capable, I will surely add it up to this list.

Ok, that’s all…Here’s the list goes…

Best Plagiarism Checker Tools to Calculate the Originality of Content


WriterZen is a content creation platform equipped with lots of tools.

  • Keyword explorer
  • Topic discovery
  • Content Creator
  • Plagiarism checker

If you are a professional writer, blogger, content marketer, or SEO, WriterZen would be your perfect match.


Because it allows you to:

  • Build content outliners (which topic to write on for online articles, essays, and documents)
  • Write content with its content editor
  • Collaborate with team members
  • Check plagiarism

WriterZen’s plagiarism checker is sophisticated. Here are a few features.

  • Check plagiarism on the sentence level. Unlike most other apps, WriterZen checks similar content on each sentence.
  • Include exclude domains from checking similar content
  • Adjust the level of scrutiny set for the Plagiarism checker

And the best part is Writerzen is a free online plagiarism checker with percentage scoring. Its free plan lets you check up to 5,000 words of plagiarism per day. If you upgrade to the Premium plan, you can check up to 30,000 words per day.

First of all, head over to WriterZen and create your account.

Once done, go to the Plagiarism Checker page and click on the “New Project” button.

Writerzen plagiarism checker

Once clicked, you will be shown a popup similar to the below.

enter content
  1. Enter the project title. If you want to check content of your school essay, type the essay title.
  2. Import content. There is two ways. One is copying and pasting. The second is importing from a .txt file.
  3. The minium text length is 20 words and the maximum words length is 5,000.

WriterZen will scan the web. It usually takes less than a minute.

collecting data writerzen

Once done, you will see your plagiarism report. On this page, you can exclude any domain, share reports with others, and see plagiarism scoring with percentage (higher the worst of plagiarized), and see unique sentences and plagiarized sentences.

The screenshot above shows the plagiarism report for text copied from an article about ContentStudio.

Since the free plan of WriterZen allows you to check up to 5,000 words a day, it’s sufficient for any normal user. If you want to extend the limits, I recommend premium plans. It’s worth the investment.

This lets us to the next plagiarism checker app.

Grammarly Plagiarism Checker


Grammarly is my personal writing aid that I use entirely every day.

Grammarly is a powerful online grammar checker, punctuation corrector, better proofreader, and in fact, a perfect vocabulary builder that can make your articles errorless, easy-to-read, search engine friendly, and human-friendly.

I am not going to be very detailed about Grammarly here. But, if you want to learn more about it, refer to my comprehensive and unbiased Grammarly review article.

Grammarly offers all manner of tools for article writers, researchers, entrepreneurs, content marketers, students, and webmasters alike as a writing tool. One of the most renowned tools is the “Grammarly Plagiarism checker.”

Once you created your Grammarly premium account, you are ready to scan ANY document for finding plagiarism.

Here’s How it works…

Step #1: Log into Grammarly Account and upload your document. (You can also use the text editor to write your document. Grammarly automatically saves your article, so you can edit your article from anywhere you are)


Step #2: Hover over the “Plagiarism” icon on the left sidebar and enable the plagiarism checking feature.

Step #3: Wait a few seconds till Grammarly’s plagiarism tool scans indexed web pages to find content equalities. Once Grammarly scans over and detected ANY similar sentence or words, they will be underlined by a yellow line.

checking similar content on Grammarly

Look at this screenshot. As you see, Grammarly has identified that a few sentences are already put in somewhere.

You can find the text “Unoriginality” or “Plagiarism” percentage in the writing score box. The higher the number, the better work you’ve done.

To find the web page URL of copied content located, click on the underlined text.

Grammarly works online as a web application and works on your PC, laptop as well. So, if you want to check plagiarism for articles you write in Microsoft Word, you’re just a few clicks away from doing that.

All in all, Grammarly’s Plagiarism Checker is an efficient tool to detect copied content. The best part is it comes for free with its premium plans. Learn more about Grammarly’s free and paid plan differences.

If you have a team, Grammarly Business would be a good choice since your team members can check content plagiarism easily. So, if you’re looking for a perfect tool that checks grammar and punctuation online while work as an excellent plagiarism checker, I recommend you to use Grammarly.

Small SEO Tools’ Plagiarism Checker

smallseotools plagiarism checker
smallseotools plagiarism checker

Another useful tool is to detect already existing content on the entire Internet. SMallSEOTools.com provides various SEO and content writing tools. Its plagiarism checker tool is a relatively new one. But, it has proven to work very well for many document types.

The best part is it is a free plagiarism checker tool. So, you don’t have to pay a fee and, on the other hand, don’t have to download any software you work with. It detects content piracy seamlessly. But, the downside of this online anti-plagiarism tool is you’re limited to 1000 words per search.

But, the downside of this online anti-plagiarism tool is you’re limited to 1000 words per search.

So you couldn’t check over 1000 words in a search. However, Small SEO Tools provides an excellent free plagiarism checker for school kids, college students, and teachers.

Once you pasted your content, you could start detecting plagiarism by clicking on the “Check Plagiarism” button. After a few seconds, you will see the result. If any sentence already exists on the Internet, it will be marked in red color. That means you have to rephrase those to minimize the duplicity content rate.



DupliChecker is another free online plagiarism detector that perfectly suits students. As SmallSEOTools’s plagiarism checking tool, the main con of this tool is you are limited to check up to 1000 words per search or article.

The Plagiarism Checker by DustBall.com


Another simple, easy-to-use free plagiarism scanner tool. This tool also works similarly to the above tools. As the DustBall.com website claims, it is a free plagiarism checker for teachers. Test it and see whether it can check the homework and assignments of your students efficiently.



The most popular anti-plagiarism checker tool for many webmasters and bloggers. Unlike other plagiarism checker tools, CopySpace detects plagiarism-only web content. That means you have to enter a URL to find already existing content that is slightly similar to your article.



Another useful tool is to find duplicate content on the Internet. If you’re a webmaster and an SEO, you are going to like this tool. Because not only can you find duplicate content on your website or blog, but also other essential SEO metrics such as broken links. SiteLiner is a free plagiarism detector tool. So, go now and find whether your website has a duplicate content issue on your site.

SiteLiner is a free plagiarism detector tool. So, go now and find whether your website has a duplicate content issue on your site.

Meanwhile, don’t forget to check what Google says about Duplicate content over here.

Plagiarism Checker by SEOToolStation.com


The seventh of my best online plagiarism checker tools list is the Plagiarism checker by SEO Tools Station. As the name implies, this website provides different online tools for SEO purposes.

Content marketing is a part of SEO now. Writing 100% original content has become an essential thing in the search engine marketing space.

That’s why SEOToolStation.com developed an excellent free plagiarism checking tool for webmasters.

You can scan ANY content to find duplicate content. They support all these three methods.

  1. Copy and paste (or write) article in online tool
  2. Upload your .docx/.txt file
  3. Enter the URL

But, like other free online plagiarism checker tools, the downside of this one is you’re limited to check up to 1000 words per search. Give this tool a try and see whether it suits your needs.

Other Plagiarism Checker Tools & Programs Worth Trying…

After I had researched the internet, I found a few helpful plagiarism checker tools and software. So, I thought you’d like to try them out. Here are them:

  1. QueText – A completely free plagiarism detector. Your document will be analyzed based on lexical frequencies, phrase patterns, and many other factors. QueText ignores quotations and common phrases. And it is a plagiarism checker online free with a percentage. So you could find how many amounts of the entire article is plagiarized.
  2. Plagiarisma – A multilingual plagiarism checker tool that currently supports over 190 languages. You can download plagiarism software free for computers or use the online tool, their web browser extension, or install the mobile app on your android and blackberry phone.
  3. Plagium – A thorough plagiarism online tool that comes with handy features such as compare text, filtering “Relevancy fair.”
  4. PlagTracker – Yet another free plagiarism lookup tool that works similar to Small SEO Tools.
  5. PlagScan – A paid plagiarism checker tool with flat rates.
  6. Viper Plagiarism Scanner – Viper Plagiarism Scanner by ScanMyEssay is software that can be used to detect similarities between multiple documents. It is a good alternative to Turnitin (WriteCheck).

Find Words on Best Plagiarim Checker Apps

It is a reasonable thing to get your article plagiarized. However, I have lots of experience in how content theft matters for business. I have lost hundreds of valuable customers: subscribers and loyal readers due to unknown content plagiarism issues.

You may not know that you’ve made a copyright infringement. You might not feel there is anything wrong with your business. And you haven’t done any guilty.

But the time goes the branches will spread like cancer. So, before being a plague, you must get rid of plagiarism issues.

I personally use Grammarly for my writing activities. While Grammarly primarily is a grammar checker tool, I also don’t forget to use its Plagiarism Checker every time I am ready to publish an article online.

I don’t insist you use Grammarly, but I can suggest you use Grammarly at least once to try it for your next plagiarism check for your essay, assignment, legal letter, and email.

So, what is your best plagiarism checker tool or program? Share your opinions in the comment form below. I will reply to every comment you share.


4 thoughts on “14 Best Online Plagiarism Checker Tools for Writers in 2021”

  1. Chamal, many thanks for sharing the list of your favorite tools, I’ll check them out. Have you heard about a plagiarism detector called Unplag? I’m using it for five months already and would like to recommend it to other bloggers. There is also a free plagiarism checker< available online. I bet you'll enjoy using it and probably include to your personal list of plagiarism detection tools soon. There is no place for plagiarism and content theft on ProBloggingTricks! Cheers

  2. Chamal this is a great list. Another tool I would add is Copyleaks As a blogger I’ve been using this the past 5 months after seeing my content was being taken and duplicated on a few other websites I did not give permission to. I suggest this for anyone publishing content online!


Leave a Comment

1 Share
Share via
Copy link