The Best Paid Plagiarism Checkers

If you’re writing for a business website or a college paper or even just a personal blog, it’s important to avoid plagiarising content. The might be an obvious thing to say to writers and marketers who avoid copying content, but there are a few reasons why a plagiarism checker makes sense.

  1. We are all products of our influences and sometimes we use someone else’s words without realizing it. Unintentional plagiarism can lead to the same consequences as intentional plagiarism.
  2. If you hire writers to help with content, landing pages, and emails, it’s important to check their work for plagiarism. Whether your contracted or staff writers mean to copy the content or not, you can’t take the chance that you might inadvertently publish copied content. 
  3. Plagiarized content on the internet will almost always struggle to rank well on Google. The algorithm that power’s the world’s most popular search engine is designed to favor unique content. Originality is key. Plagiarised content is generally (but not always) useless for generating organic traffic to a website.
  4. There are legal reasons for avoiding plagiarising content. Companies have been sued and journalists exposed for passing another creator’s content as their own. Students have lost grades and authors have been financially bankrupted thanks to their use of copyrighted material. 

The solution is to use high-quality paid plagiarism checker software. Sounds straightforward, right? But not all applications are equal. In fact, some industry-standard checkers are downright terrible at discovering duplicate content. People are still using plagiarism tools that were good 10 years ago. Times have changed. 

If you’re serious about making sure that the content you publish is unique and original, you will need a plagiarism checker. Now, you might ask if it needs to be a paid product. In most cases, the answer is yes. Paid plagiarism checkers are better. But not always. Read on to learn about the best plagiarism checking products and one free plagiarism checker, which is just as good as the rest. 


Copyscape is a tool favored by businesses, universities, and marketing companies. If you buy content from a content marketing agency, you will generally receive a “passed Copyscape checks” stamp of approval. 

But is Copyscape the best? 

While Copyscape may be a tool people turn to for checking the uniqueness of a piece of writing, I would argue that it is not the best tool for this job. In fact, I believe that it is one of the least reliable tools. There are far better options out there for people looking to check the uniqueness of their writing.

Why is it so popular? Copyscape‘s popularity seems to stem from its reputation and longevity. It’s been around forever, everyone knows it, and people presume it’s the best because others have said so. 

I recommend you test some writing samples in Copyscape and then test the same content in other tools. The difference in quality might shock you. Try the best tool to see what I mean.


Check for plagiarism regularly so that your rankings remain strong and Google recognizes your ownership of your content. Use PlagiaShield, a fast and accurate plagiarism detection service, to ensure all pages on your website are original.

plagiashield plagiarism checker tool for websites

PlagiaShield helps you identify content thieves, prevent articles with copied content from being uploaded, and identify backlink opportunities. Other tools require you to check URLs individually, but this tool can check your entire domain at once and monitor changes at the same time. 


If you’ve been writing for the web for any amount of time, you’ll probably have heard of Grammarly. But did you know that the world’s most popular grammar checker tool and proofreading app also has a plagiarism checker?

Most people use the free version of Grammarly but it’s worth upgrading to a paid plan to get all the features (clarity-focused sentence rewrites, consistency, compelling vocabulary, and more) that have made the tool the standard for proofreading on the internet. And with a paid plan you also get Grammarly’s plagiarism checker in your web browser, Google docs, native Windows and MacOS apps, mobile phone apps, and Microsoft Word. 

Grammarly’s paid features are one of the more expensive on this list at around  $12 a month. However, you get the full suite of writing tools along with the plagiarism detection tool with a paid subscription.


This tool is not a purpose-built grammar checker, but hear me out when I say that content creators will love one of the newest features.

‘Originality Score' is the latest addition to Frase, our choice of content writing assistant and SEO research tool. This new feature will help you to assess the uniqueness of your content and make sure that it is of the highest quality.

This neat feature tells you, through a small circle in the top right corner of the editor screen, where your writing is similar to something on another website. Clicking on this allows you to see exactly which part of your writing is similar, and how much of it is. This is really helpful when you're trying to make sure that your writing is unique and not plagiarized.

Frase goes further than simply flagging identical sentences. Many plagiarism checkers look for exact match sentences. Frase checks for similar fragments: The wording might be different but the meaning and structure could be similar.

Just something to keep in mind – you may or may not want to make changes based on what you learn, but it's always good to be aware. The more you know, the more control you'll have over your writing.

And you can then use Frase's unique AI writing capabilities to create content with the push of a button. Highlight the text and choose “rewrite” from the context menu. Easy!


QuillBot's Plagiarism Checker will help to make sure that all of your text is properly attributed to its original authors. And of course, it will also help prevent any unintended plagiarism. It’s a very useful tool for writers, bloggers, journalists or anyone who needs to cite a source.

Ideas can be plagiarized just as easily as words, so taking someone’s idea and rewording it without citing the original source is stepping over the line.

QuillBot understands text in more than 100 languages.

A Premium subscription allows you to scan up to 20 pages per month.

QuillBot not only protects you from being sued, but it’s also an intelligent grammar checker and spell-checker that makes writing easier. Plus, the free-to-use rewording tool can make even the most boring pieces exciting thanks to AI-enhanced writing capabilities. is the world's first AI-powered plagiarism checker and AI detector for serious content publishers.

It was created to identify content written by AI that uses the new GPT-3 algorithm, which can produce text that is original and human-like. 

Large businesses and organizations use GPT-3 to produce content that appears to have been written by people but hasn't. 

And you should be aware of this if you publish online!

By identifying AI-generated content before it is published, can assist you in avoiding penalties from Google and other search engines. 

Additionally, it's a useful tool for content marketers and editors who are sick of wasting time manually checking content for plagiarism or relying on automated tools that don't always do the job correctly.

To help you decide what to do next, you can get comprehensive information about each piece of content in a clear and easy-to-understand interface.

Surfer SEO

Surfer SEO, one of the most popular tools for optimizing website content, recently added plagiarism detection to the Content Editor (a tool that analyses your writing in context to determine its chances of ranking high in Google for a given keyword).

When optimizing your text for your website, you can now perform thorough and in-depth plagiarism checks.

To use the tool, open a Content Editor draft with at least 50% of the recommended word count, navigate to the “Tools” menu, and select “Run Plagiarism Checker.” The check results will be displayed in the right pane, with plagiarized passages marked in red.

Make changes to remove plagiarism or simply ignore it. The choice is yours, and the software will only make suggestions. You have full control. If you're already a user of the software or you're looking for a tool that helps with optimizing content for the web, this is a handy free addition to an already powerful toolset. 

The plagiarism checker is free for all active users of Surfer SEO's content editor and can be used as many times as necessary with a 10-minute wait period between scans. 

The duplicate checker uses Surfer's unique analysis to identify duplicate content on SERPs. The company plans to introduce unique paragraph suggestions in the future.


UniqueText supports users in developing plagiarism-free material Well, that's just like the other tools, you might say. You'd be correct, but this tool is still worth investigating. Having used the tool for a considerable amount of time, I strongly encourage you to try it out.

uniquetext duplicate text checker software

UniqueText discovered the most hits after running many sorts of texts in various genres and niches through all of the plagiarism checkers on this list. And, while many of these hits may be insignificant or unimportant (the sensitivity level might need tweaking), UniqueText frequently reveals instances of plagiarism where other techniques fail to detect anything.

Website owners, publishers, and bloggers who seek to post only original information should consider using more than one plagiarism checker tool. Personally, I run many checks on every piece of content before publishing it, and UniqueText is always on the list.


Quetext is a Kansas City-based company that focuses on one thing, plagiarism detection. And it achieves its promise of accuracy, privacy, and integrity.

Quetext is a simple tool with a powerful backend. The software’s Deepsearch ™ technology, which uses contextual analysis, fuzzy matching, and conditional scoring to produce a detailed plagiarism report.

While the website promises a fast search, don’t expect instant answers. You might have to wait for up to a minute for results. In some ways, it’s comforting to know that the Deepsearch algorithm is going “deep” on the internet to find any connection between your query and what’s already published on the billions of websites out there. 

Quetext also offers a citation assistant. This is useful for academic paper and scientific paper writers who want to create citations to articles or research papers they reference (or copy verbatim) in their writing. 

You can exclude certain sources (for example your own website and review sites) and every search generates a report that you can refer to at any time. Results are displayed with color-coding to show exactly what parts of the text are potentially “copied”. Clicking on each section of the text displays the source. 

The Premium plan costs $9.99 a month after a 3-day free trial. The “free” version is a limited set of searches that give you a pretty good idea of the quality of results. 

It’s a wonderfully simple tool with lots of potential. 


ProWritingAid is one of the best tools for improving your writing, and I recommend it to everyone. There’s also a plagiarism checker feature, which is extensive, but expensive. At the lowest plan, each check costs $1. Buy 1000 checks for $200 and each check works out at 20c. Still more expensive than Copyscape, but it’s a lot better than that tool. It’s worth considering ProWritingAid’s Plagiarism Check service as a backup service to support your primary tool. It’s no harm double-checking important pieces of content. 

ProWritingAid's new rephrase tool has made it even easier to edit and improve content so it doesn't fall foul of plagiarism black marks.


WriterZen is a content creation platform that helps writers find keywords, keyword topics, and build content based on artificial intelligence recommendations. Instead of switching between keyword research tools, writing apps, and plagiarism checkers, writers can concentrate on writing. No more switching back-and-forth between apps. The free plan allows you to check up to 5000 words per day for plagiarism, so it's worth signing up for a free account.

While you're there, make sure you check out the other cool features for writers. 

Small SEO Tools

This is a completely free plagiarism checker that comes as part of a suite of SEO tools for plagiarism. The site relies on display ads to support the processing of the millions of visits a month to the site. And while the results are good, the ads are one aspect that will not only distract you but slow your progress. 

It’s hard to even find the check plagiarism button. It’s usually buried under a jumble of ads. In addition, you’ll need to complete the reCAPTCHA every time you want to run a plagiarism check. It might not sound like much, but once you’ve used a premium tool like Quetext or Writer, the clutter of the Small SEO Tools website can be off-putting. 

One nice feature is the ability to upload different file formats like .doc, .pdf, and .odt. You can also select files directly from your Dropbox or Google Drive storage. And of course, as with the other tools, you can simply paste text into the entry field. 

After you’ve run your checks for plagiarized content, you can also click the “Check Grammar“ button for a free grammar check. It’s nowhere near as thorough as Grammarly or ProWritingAid, but it’s a good first check and can act as a backup check to support premium products. 

Small SEO tools for plagiarism also offers checks in languages such as Spanish, French, Chinese, and German. 

Frequently Asked Questions

Are plagiarism checkers accurate?

Some plagiarism checkers are better than others at detecting specific types of plagiarism. Some methods, for example, might be particularly effective at detecting outright copying, but others may be better at detecting paraphrased text.

Keep in mind that plagiarism checkers arewere created to help you avoid copyright issues by detecting most cases of plagiarism, but they are not error-proof. The extent of a plagiarism checker's database may influence its accuracy. Those that have access to larger databases can cross-reference more content, resulting in more precise results.

Potential problems include

  • False positives: Even the most experienced checkers can detect inadvertent matches or popular phrases.
  • False negatives: Clever plagiarism may elude detection, especially with simple technologies.

What is the most affordable plagiarism checker?

Small SEO Tools is the most economical plagiarism checker (it's free). As part of a package of SEO tools, this portal provides a completely free plagiarism checker. It is supported by display ads, so you can use the plagiarism detecting tool for free. However, these adverts can be overwhelming and that each check might require completing a reCAPTCHA. Small SEO Tools provides a realistic, cost-effective solution for individuals or businesses without investing in a premium service. However, while it is inexpensive, the quality, speed, and user experience may fall short of those of premium services.

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