[Complete Guide] Best Free Plagiarism Checkers for Your Content

Writerly

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When writing content, ranking well and reaching the broadest audience is everyone’s main concern. To achieve that, your content has to have flawless grammar, an interesting and relatable topic, and some well-researched (low-competition) keywords strategically placed throughout. But even more importantly, your content has to be original. That way, it will be relevant to your audience and adhere to the plagiarism rules of search engines.

Now, as you probably already know, most plagiarism checkers aren’t free. If they are, it's just a free trial that you can use. In addition, most of them don’t offer all their services as a part of the trial, so you can’t enjoy the full experience.

However, there are many checkers that are advertised as free, and they offer you different advantages. Still, when you decide to check what those advantages are, you come up empty, as most of these sites aren’t really transparent with their advertising.

To that end, I’ve decided to check out and test the most popular free plagiarism checkers and get some answers. Are they truly free? Do they work? And how do they compare to paid services?

I used three different articles to test the checkers:

  1. For the first one, I used text directly copied from different online sources (Wikipedia, several popular articles, etc.) — in other words, it was 100% plagiarized.
  2. The second was the same plagiarized article heavily edited to rephrase the problematic parts.
  3. The third was an article that was 100% clear on Copyscape and Grammarly (both paid plagiarism checkers).

Here’s what I found:

1. Quetext

When you look up free plagiarism checkers, Quetext is always everyone’s go-to recommendation. That’s why I decided to test it first as well.

For the first article, it identified every source I had used to make it, which was a nice surprise. It also showed matches with other articles I hadn’t used, though. Upon closer inspection, I saw that some were actual matches, but others were false positives. These false positives were flagged via some common words and phrases (mostly transitions, such as first and foremost, it goes without saying, or common sentence structures, such as there are several different types…). Some of these sources that Quetxet found were not related to the topic of the article, which is more proof that these were indeed false positives.

The second article had a much lower plagiarism score since it was mostly rewritten. Still, the checker correctly pinpointed all the sources I left scattered behind. However, there were even more false positives this time around. Such scores can be quite detrimental, as they make you think you have to change standard wording that can’t really be plagiarized. For the sake of comparison, Copyscape only flagged the actual sources I copied sentences and phrases from.

And finally, Quetext found the original article I wrote to be the most unique. Again, it found far too many false positives with different articles across the web, but at least it gave the deserved high score.

As far as usage goes, Quetext is quite easy to get the hang of. You can jump between sources effortlessly, and partial and total matches are colored differently. Furthermore, you can easily copy your content into a big box on the homepage. However, you can’t upload files or links.

But, as you probably already know, Quetext has one big downside for its free users. Namely, the articles you check cannot exceed 500 words. Moreover, you can check only five 500-page articles at a time, after which your free trial expires. If you subscribe for a free account, you’ll be able to check 5 articles every day.

To grapple with this problem, most people chop up their content into the size that Quetext allows. However, doing so defeats the purpose of checking your content in the first place, as certain parts might be clear while the article as a whole shows an entirely different score.

All in all, I’d say that this checker is fairly accurate and the easiest to use out of all of the ones I’ve tried. However, it’s only a good choice if you have a few shorter articles to check each day. If you have more content and you know you’ll use the checker often, it might be a good idea to actually pay for the first-tier subscription plan ($10.49 a month). It includes checking 100,000 words per month, as well as the option to upload 5 bulk files at a time.


2. Check-plagiarism.com

Check-plagiarism.com is the checker that offers, by far, the most benefits to free users. Surprisingly, the ads for this checker proved sincere, as you can tell exactly what you get for free by reading the pricing page on the official website.

If you decide not to buy the premium version, you can check articles of up to 2,000 words at a time. You can do this an unlimited number of times, as long as the article doesn’t exceed the 2k-word limit. Besides copying and pasting your content into the checker, you can also upload it from your computer or drive, whichever is more convenient.

Now, the checker goes through your text sentence by sentence. In other words, it doesn’t compare your whole text against its database, but only your individual sentences. In some instances, this approach works, but in others, it falls a bit short.

The article I compiled by copying sentences from different sources was flagged immediately. However, the sources I only copied one sentence or two from weren’t flagged at all. Still, the checker found the exact sources in most cases and highlighted the sentences clearly.

Things were a lot clearer with the article I tinkered with. I found that as long as I changed a sentence just a little bit (used synonyms, for example), the checker was quite easy to fool. It seems that it only looks for exact matches, so it’s easier to pass if you rephrase your content slightly.

And as for the article that I know is unique — this checker thought the same. There were no hits at all, which was a nice surprise.

When all is said and done, this checker proved better than Quetext when it comes to false positives. There were barely any with check-plagiarism.com, which I appreciated. But it seems like, in order to avoid false positives, they created another problem. Namely, a sentence has to be a complete match for the checker to catch it.

Still, this checker allows for longer texts, and it can catch the plagiarism of online articles and academic sources alike. It’s definitely a good choice if you run a blog and your content doesn’t exceed 2k words. You can easily scan such articles multiple times a day and be sure that you will get pretty solid results.

Finally, I also have to mention one interesting feature I noticed. Check-plagiarism.com allows you to pick one URL that it won’t include in the plagiarism search. This can come in handy if you are allowed to use something as a source and don’t want it taken into account during the analysis.

If you like this checker and want to try out the paid version, you can choose one of their subscription plans. The first one starts at $7 per week, and it lets you check up to 125,000 words every month.


3. Unicheck

When I was searching for free checkers, Unicheck popped up immediately. But when I clicked on it, I discovered that you can only check 200-word documents for free. Otherwise, you have to pay and subscribe. It’s not likely that your content will be so short; therefore, you will most probably need to pay for the premium version.

I shortened each of my test articles to use the checker, leaving as many relevant parts in as possible but staying within the limits.

The checker flagged the fully plagiarized article easily, and it provided URLs with the sources. However, it matched the same parts with different sources more often than not. Thus, it was difficult to see what I should change to avoid plagiarism. Plus, the tool highlighted everything in the same color, so it was difficult to orient myself and find the right sources at first.

Similarly, the checker did a pretty good job with the edited version of the plagiarized article but still showed many false positives. In this instance, it showed even more matches for single sentences and phrases, meaning that it wasn't that reliable. Still, it shows you what to change in order to fix the problem.

There were some false positives in my original article as well, but they were all common phrases or transitions. In that regard, this checker was similar to Quetext.

What I like the most about this checker is that there is a live chat you can use at all times. So, you can easily get help and learn how to use the checker to get the best possible results.

Unicheck’s lowest tier costs $10, and it allows you to check 50 pages per month (amounting to 13,750 words in total).


4. Plagiarism Detector

Plagiarism Detector was definitely the most frustrating checker I’ve tried on this journey. The site was buggy and took ages to load. Even worse, I waited to get my plagiarism results for as long as 20 minutes.

At first, I thought it might be my own connection, but everything else was working seamlessly. Then I checked some reviews and saw that a lot of people have complained about this issue as well. So, be warned.

This tool lets you check articles of up to 1,000 words for free. As far as I can tell, you can do it unlimited times, but I couldn’t wait 20 minutes per check to actually test whether that’s true.

Now, onto the checker itself. It did pick up on every source correctly, and there weren’t many false positives. However, somewhere along the way, it stopped showing the flagged sources completely. I could see that a sentence was highlighted, but there was no source connected to it.

This issue happened with the first article I checked and not the second and third. Still, it’s a major con for this tool, as a checker that doesn’t show you sources isn’t really that useful.

Aside from this, the tool wasn’t bad. It did show some false positives, but it was more or less successful in flagging actual plagiarized content only. Matters got a bit messy with the second (edited) article. Namely, the tool showed me five different sources for a single phrase or sentence.

The final verdict is as follows: if your articles are all <1,000 words and you don’t mind the bugginess and wait, check this one out. But personally, I would stick to any other choice on the list.

It might also be possible that the paid plans offer a better user experience. The first-tier plan costs $10, and you can check 72,000 words each month.


5. DupliChecker

DupliChecker was my next stop, and the results were average.

Just like Plagiarism Detector, this one scans documents of up to 1,000 words. It recognized most of the plagiarism in the copied article I pasted (about 80%), and the sources were easy to navigate.

Similarly to Check-plagiarism.com, this tool looks through documents sentence by sentence. So, some things might get lost in the checking process, which was the case with my paraphrased article. Although the site advertises the checker as one that can catch paraphrasing, it didn't live up to expectations. In fact, it mostly recognized that article as clear, when I just changed some words or added them.

One fact that really threw me off was how confusing the site is. It took me a while to get my bearings, and even then, the constant blinking ads and pop-ups were quite a nightmare.

But all in all, the tool itself is okay. Checking doesn’t take long, the tool analyzes every sentence, and you can easily change your text to avoid plagiarized content as you go through it.

As for the paid version, it starts at $10 per month. If you opt for this checker, you will be able to check up to 30,000 words.


6. 1text

Interestingly enough, 1text has one of the easiest interfaces I’ve ever used. There is no confusion when looking at the results, and pasting your content into the checker is seamless.

While you can check articles without signing up, their number is limited. But if you sign up for free, you’ll be able to check up to 15,000 words per month. The paid version starts at $10.60 (€9.99), and you can use it to check up to 150,000 words.

If you use the free version without signing up, you’ll likely have to wait a bit since those with accounts take precedence. For example, before signing up, I was 19th in the queue and had to wait about 5 minutes for my results. But after I signed up, the results took only a few seconds.

As for the results, I found them quite mixed. For my plagiarized article, the checker identified about ⅔ of the sources I used. This result is not bad, but it’s problematic if you want a checker that will help you post completely original content.

Things were slightly better with the article I paraphrased, as it picked up on most of the sources. The 100% clear article was also flagged, but it was mostly due to false positives found in articles in different niches.

One thing I’d like to add is that 1text doesn’t allow you to click on plagiarized sentences in order to see their source (like Quetext does, for example). This fact makes it a bit difficult to identify and correct plagiarized parts.


7. Small Seo Tools

Like most checkers I've tried, Small SEO Tools lets you run articles that are up to 1,000 words long. It’s not clear from the website how many checks you can perform for free, but I ran every article twice without any issues. The site does require you to fill in a captcha before uploading a document, though.

The checker was pretty successful with my plagiarized article, finding about 90% of the sources. However, it performed horribly with the article I edited. Namely, it only found about 20% of the sources I used, which is quite poor compared to the other checkers I’ve mentioned.

I’d also like to mention that the reports the tool provides are a bit confusing, as everything is highlighted in a single color. Also, it’s somewhat difficult to match a sentence to its source.

Since I used the free version, I had to wait a few minutes for each of my checks to complete. However, I’ve seen that this waiting time is eliminated when you pay for one of the subscription plans. If you’re interested, the first one starts at $4.99 per week and allows you to check 15,000 words.


8. Search Engine Reports

This tool is completely free if you’re okay with scanning articles of up to 1,500 words. If so, there is no limit to how many of them you can check per day. If you want to remove this limit, you can sign up for any of the subscription plans that start at $10.

The tool was moderately successful in detecting plagiarism in all the articles I checked. I’d rate it in the same range as Pre Post SEO and 1text. So, it’s quite average, but it can at least point you in the right direction while you are editing your content.

One issue I noticed was that, even if it marked the article as 100% plagiarized, the tool only highlighted certain words and phrases. Thus, it is difficult to gauge what you need to change to avoid plagiarism. In addition, the checker had trouble pinpointing the exact source the content was copied from, making the reports even more unreliable.

What irked me the most about this checker were the constant ads and stuffy layout. It was a bit difficult to navigate the page with so many distractions, and my tired eyes didn’t appreciate the exercise.


9. PrePost SEO

I’ll also include a few words about PrePost SEO’s plagiarism checker. Like some of the other options on this list, it lets you scan articles of up to 1,000 words at a time. If you want more, you can pay for one of the subscription plans. The cheapest one is $10 a month, and it allows you to check 5,000 queries (sentences) every month.

This tool was mostly able to find partial matches, and lots of them were false positives. It will flag an entire sentence as plagiarized only if you copied it from a source in its entirety. Otherwise, it will most likely mark it as clear.

I was intrigued by this checker because it is advertised as a tool that can distinguish between paraphrasing and outright plagiarism. When I tried it, it did indeed highlight my articles with two separate colors for these two instances.

However, it wasn’t that reliable in its quest. More often than not, it marked whole copied paragraphs as simply paraphrased, and vice versa. So, the company might be onto something, but they definitely have to work a lot harder to make the feature fully operational.


10. Grammarly

Lastly, surprisingly (or not), Grammarly always pops up when you search for free plagiarism content. Why that is — I have no idea, as the checker is anything but free. Still, I decided to include it here, so you know what to expect since it is so popular.

Namely, Grammarly allows you to upload or paste your content into the checker, as well as analyze it for plagiarism. But that is where the free features end. You get your content back with a bunch of highlighted sentences, but no sources at all. So, you’ll have to guess what to change and pray you get it right.

I’m not sure how accurate the checker is because even my original article got a few highlighted bits, which shouldn’t be the case, as I had it cleared in the paid version. But in any case, this checker shouldn’t be advertised as free, and you shouldn’t waste too much of your time with the free version.

The paid version starts at $12, and there is no limit to how many words you can check. Moreover, the paid checker is also quite accurate, so it is a worthwhile investment.


And, that’s it, folks. While I did check a few other tools (Plagiarism Checker.co, Plagium, and Writer, among others), they performed rather poorly or allowed a word count that simply wasn’t relevant. So, if you need a free checker, let it be one of those discussed above (except for Grammarly, which isn’t even free). Personally, I’d opt either for Quetext or Check-plagiarism.com.

All things considered, there are quite a few checkers that allow you to scan your content for free. They might show a lot of false positives and be a bit slow, but they are usable. If you don’t make content that often and just want to check it from time to time, these checkers are indeed a good choice.

But if you plan to devote yourself seriously to writing content and posting it regularly, I’d definitely consider paying for a subscription plan. It can be any of the checkers I covered above, or another one completely. For one, it’ll save you a lot of headaches and time. Plus, there are quite a few checkers that are affordable in the long run, so your wallet won’t suffer too much, either.

In any case, we’ve come to the end of this little experiment. Feel free to share any checkers you use or to talk about your experiences with the ones I’ve mentioned. I’m looking forward to learning even more about them!
 
My personal opinion.
1text is by far the more advanced plagiarism checker I have ever tried. No need to compare it to the likes of copyscape.
At times, it gives a lot of false positives as there's more than one way to skin a cat.
But the good thing is that it easily picks up rewritten/rephrased content.

PS: as somebody mentioned it not so long ago... if a simple russian tool can easily pick up rephrased text, what makes you think google can't?
 
@MisterF was the one who highlighted that crappy scape was bad, and until then I used to rely on it a lot, however after testing quetext I asked all paid orders to be run via it and though some sellers argued they fell in line so for me quetext is the best and wish someday it’s made mandatory here be it guest posts content or content for sites etc.
 
Thanks for sharing this guide, it is obvious you put in the work.

But I don't agree with the list, and I only use huggingface
 
I have Bookmarked your valuable guide
 
@MisterF was the one who highlighted that crappy scape was bad, and until then I used to rely on it a lot, however after testing quetext I asked all paid orders to be run via it and though some sellers argued they fell in line so for me quetext is the best and wish someday it’s made mandatory here be it guest posts content or content for sites etc.

Yeah I have used Quetext for a long time and it's great.
 
1text is levels above the others
 
What is an acceptable percentage of plagiarism?
 
Thank you for writing this long and detailed guide. I have bookmarked it. It will be helpful to many for sure.
 
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