With well over a million monthly searches for plagiarism checker related tools, it’s no wonder that so many sites are eager to capitalise on the demand for plagiarism scanning software. In fact, many of the top plagiarism checkers claim to be free – so why would students ever pay for such a service?
In this post, we look at some of Google’s top results for plagiarism checkers, and we consider why trusting your plagiarism scan with these services might not be the best option for you.
1. Grammarly
Grammarly took the #1 spot in our Google search and promised that with its tool, we could ‘ensure every word was our own’. It claims to detect plagiarism and check for other writing issues too.
We fed Grammarly 907 words of dummy Latin text: a combination of the ‘Lorem ipsum’ paragraphs that you often find in sample documents, which appear all over the web – so it ought to result in a generous amount of matches.
Despite the entire document being 100% plagiarised, Grammarly confidently marked it as completely plagiarism free, although it suggested there might be an issue with our spelling (no kidding) and prompted us to sign up. Once we did, it asked us a few questions and insisted we download either the app for Windows or the browser extension. Of course, we were nudged to upgrade to one of their paid plans (starting at £25 per month) at every step of the way, but we continued to choose the free options.
Finally, on opening up the app, we added our test document and we were given a score of 99/100 for the quality of writing, despite the fact that it was written in dummy nonsensical Latin. We also found that without asking for any permissions, it had installed an add-on to Word with constant irritating popups aimed at getting you to upgrade. Needless to say, we uninstalled Grammarly very quickly.
2. PlagiarismDetector.net
Our second Google result was PlagiarismDetector.net which had a cut and paste box on the front page. 1,000 words are included in the free online plagiarism check – just enough for our test document!
The scan was fairly quick, taking about a minute, and the results indicated 96% plagiarised content which is a reasonable assumption. However, the detail of the results was just bizarre. There was no match greater than 10%, with snippets flagged from all over the web. The sources identified did have matching content, but the scan failed to identify the single master source. Another oddity about the scan was that only a portion of the text – perhaps 50% – was highlighted, despite the overall percentage being 96%. This would be an extremely confusing result for a student.
3. Plagiarismchecker.ai
Our third Google result was Plagiarismchecker.ai and this site claims you can detect plagiarism or check for AI content. It suggests it has the largest database, with some 10 million offline documents scanned alongside the usual online open sources, and it promises not to save our data, or store submitted work (we quote) “in the secret repository”. This did immediately make us wonder where they had harvested the 10 million offline documents from.
The options are separate buttons. We uploaded our dummy Latin file and hit the button to detect plagiarism. Then we waited. And waited. And waited. We even left the tab open while we were checking all the other scanners. But nothing happened. We would have loved to assess how effective this free online plagiarism tool was, but we couldn’t get it to work.
4. PapersOwl.com
The fourth result in Google was PapersOwl.com, an essay writing service. These companies write custom essays for students, and they often have free tools on their website to attract potential customers to their paid services.
Papers Owl says that using its free plagiarism checker service is subject to its terms and conditions which we had to accept to do our scan. Unfortunately, there was nothing in its terms that relate to the use of the tool.
Strangely, they also requested that we paste our essay title in a separate box. This made us wonder if they planned on publishing our document down the line. There was no premium upgrade offered.
We added our test document and had a result in a few seconds. They correctly identified the main source of the material and also flagged similar content on 10 other sites, which was a reasonable result.
Papers Owl used the result to sell their editing service to us, which in fairness was a pretty smart marketing trick. The free scanner itself worked well but the lack of terms of use, coupled with the fact that they ask for a separate title and the fact they are an essay writing company, made us deeply suspicious of how any essay scanned would be used in the future. We also ran a scan of their site and this identified over 50,000 pages of ‘example essays’. You might wonder where they got all those from.
5. Duplichecker
The fifth result in Google was Duplichecker – a site that has been around for quite some time. Similar to other sites, this offered a ‘free 1,000 word plagiarism check’ whilst continually pushing Grammarly adverts at us. The interface was almost identical to PlagiarismDetector.net, so much so that we re-ran the test on that site to compare. Sure enough, both scanners pushed almost the same advertising and suffered from almost the same problems – suggesting that they are either owned by the same companies or powered by the same tech.
Like PlagiarismDetector.net, Duplichecker returned a strangely fragmented result which did not include the master document from which our file was sourced. Instead, many small matches were identified all over the web. Also like PlagiarismDetector.net, Duplichecker only highlighted parts of the text, despite suggesting a 93% overall match. We found the results very confusing and probably not too helpful for students.
Duplicheck appears to offer some premium services but with over 5,000 words of advert-cluttered text on their results page, we were frankly confused as to what they were.
6. Small SEO Tools
This 6th result, the Small SEO Tools plagiarism checker, has also been around for a long time. Like the other sites, it offers a free online scan for up to 1,000 words, with premium upgrades available.
We pasted in our test document and the scan completed fairly quickly in less than 1 minute. It reasonably identified that the document was 98% plagiarised but like many of the other scanners, it attributed the matching text to 19 different sources, failing to match the main source. Also like many of the other scanners, only part of the text was highlighted which seems inconsistent with the 98% result.
However, something far more concerning happened while we were on the site. Without warning we were redirected to what was very clearly a scam site headed ‘Dear BT customer .. you have won a prize…’. After returning to the main site, we were again redirected to another scam site, ‘Congratulations, Dear Aldi customer! You were chosen to win (1) prize!’. On spinning the wheel, we did of course “win” and we were then prompted to pay £1.95 to claim our prize – making it illegal under the Gambling Act 2005.
Given that this site is content to send you off to some extremely untrustworthy locations, we would not suggest trusting it with your valuable academic work.
7. Scribbr
Google’s result at #7 that we checked was Scribbr. Scribbr’s homepage is entitled “Free Plagiarism Checker” and offers to ensure the originality of your work “using similar software as leading universities and publishers”. We uploaded our dummy document and were prompted to create an account. The document then scanned and we were taken to a greyed out page which stated that it had a “high risk of plagiarism”. Only paying £13.95 would take us beyond this report.
So in effect, this is not a free plagiarism check at all. It is just a doorway to persuade you to pay for a check.
8. CitationMachine.net
The next site on Google’s list was CitationMachine.net. This offers a free scan but it does warn that the papers you upload will be added to their plagiarism database and will be used internally to improve plagiarism results.
The scan completed quite quickly but we were then presented with two options:
“See my results”, or “No, I don’t want plagiarism checks”
This seemed a bit odd – why would we scan if we didn’t want results? Almost certainly this was a paywall.
Clicking “see my results” prompted the creation of an account, and selection of our ‘school’, which only appeared to allow US schools. Having quickly enrolled ourselves in Bryn Athyn College of the New Church, we were then invited to start our 3-day free trial, with a subscription of USD $11.94 a month after that, and of course, ‘cancel anytime’. Closing this box showed us our essay which had been awarded a score of 98, although it was not clear whether this was a positive or negative score. Further, it had found only 5 grammatical errors, despite the whole paper being written in dummy Latin.
How did Viper do?
We ran our same test document through Viper, our own plagiarism checker. We got our results in a couple of seconds, which rightly showed that the entire document was plagiarised, correctly identifying the online source. All the text was highlighted, as it should be.
Viper does not currently offer a free online plagiarism check. It’s something that we have provided in the past, but the cost of maintaining a high quality scanning service has increased dramatically in recent years, and we have had to pass on those costs to our users.
However, Viper is fast and it is effective. Further, its premium service does give you the confidence that your essay won’t be stored in someone’s database or published online. We’re a well-established and transparent company with a support desk, real people you can talk to and full-time engineers – rather than an ad-ridden website run in some back bedroom in a far-off country.
Viper also offers pay-as-you-go pricing, rather than an ongoing subscription which bills you even when you’re not using the service. No student has essays to submit throughout the entire year and the pay-as-you-go model is always better value.
Finally, you can also be confident that when you perform a premium scan with Viper, your data is confidential and safe and neither your teacher nor your institution will know you’ve used the software. So paying a small fee for Viper gives you accuracy and valuable peace of mind – a combination which no other scanning apps we have used today have managed to provide.
All tests conducted on 18th November 2024. Images licensed through Envato.