Think AI content is safe to use for SEO in 2025? The results of this case study might change your mind.
I will show you precisely how easy it is to detect content generated by all of the most popular AI content tools.
Now you might point to Google’s statement that:
“appropriate use of AI or automation is not against our guidelines“
But are you ready to bet your business on that?
Google already penalized sites that were abusing AI content in March 2024.
Before that, Google were actively rewarding sites that published AI content with more traffic. But then, Google killed them all which have never recovered:
Plus the Google Search Leak, DOJ Anti-trust case, and our own SEO Myths case study shows a history of inconsistent statement vs action.
Always take what Google says publicly with a grain of salt.
My point is simple:
Using AI generated content is an uncontrolled risk because you never know how Google are going to change the algorithm. So, why publish AI content that can be easily detected as AI generated?
It’s amazing how many people are taking that uncontrolled risk with absolutely zero clue of how easy AI content is to detect.
And the problem with SEO’s, is that we always follow the same 3 step process:
Over the last 20 years, that has happened with keyword stuffing, duplicate content, spun content, anchor text, schema stuffing, scholarship links and more.
And now I’m seeing just about every writer, SEO and agency abusing AI generated content at scale. Google already gave us the warning shot in March 2024 but since then, things have got much worse.
For example:
I’ve had 3 consultations recently where US based agencies are using ChatGPT to publish medical advice along with specific drug and dosage recommendations on their clients blogs with zero oversight.
In every case, the agency had not informed their medical based clients that they were using AI to generate the content. Disgusting, immoral and unethical.
So with all of this in mind, I wanted to show you just how easy it is to detect AI-generated content in 2025 using publicly available tools.
The test process was simple:
- Generate content using 14 different popular AI tools
- Run the content through 11 AI content detectors
And just to spice it up a bit, we compared the results to our original AI content detection test from January 2023 which gave similar warnings.
Here’s what happened…
What Will I Learn?
We wanted to make this test as comprehensive and fair as possible.
Here’s exactly what we did:
Step 1:
- We generated 5 articles with 14 different AI tools.
- We used the same topic for all articles to ensure fair comparison.
- That’s 60 unique pieces of content in total using the most advanced AI models, including GPT-4o, Claude 3.5 Sonnet, and Gemini Flash 2.0.
Step 2:
- We ran every single article through 11 popular AI content detection tools
- This included multiple rounds of testing.
The results are based on an average detection score, so it’s not taking into account just one output in case the AI generator had a brain fart.
We also included 5 pieces of my own human-written content to ensure we had a reliable baseline to compare the AI content against.
The goal was clear – See if AI content detectors can really detect AI content.
Here are the results…
In the graphic below, you can see exactly what happened when we tested each popular AI content writer and generator against the best AI detection methods:
The number for each tool represents the AI detection score (out of 100).
The higher the number, the more confidently the detector flagged it as AI-generated content:
| Originality | Sapling | CopyLeaks | GPT-Zero | Quillbot | Winston AI | BrandWell | TurnItIn | ZeroGPT | Phrasly AI | Writer | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Human | 27 | 4 | 0 | 3 | 0 | 3 | 0 | 18 | 8 | 5 | 1 |
| Article Forge | 100 | 99 | 41 | 63 | 0 | 66 | 90 | 90 | 85 | 83 | 10 |
| ChatGPT 4o | 100 | 100 | 99 | 99 | 96 | 94 | 84 | 84 | 81 | 81 | 20 |
| Claude Sonnet | 100 | 100 | 100 | 97 | 98 | 96 | 72 | 53 | 47 | 46 | 20 |
| DeepSeek | 100 | 100 | 100 | 86 | 80 | 50 | 58 | 45 | 33 | 33 | 19 |
| Frase | 100 | 99 | 100 | 89 | 78 | 76 | 72 | 72 | 46 | 51 | 12 |
| Jasper | 100 | 90 | 100 | 91 | 84 | 85 | 84 | 84 | 60 | 59 | 10 |
| KafKai | 100 | 100 | 100 | 98 | 92 | 54 | 90 | 90 | 84 | 83 | 25 |
| Koala.sh | 100 | 91 | 100 | 89 | 88 | 65 | 78 | 32 | 23 | 23 | 9 |
| Phrasly AI | 100 | 100 | 100 | 96 | 100 | 95 | 32 | 77 | 84 | 82 | 17 |
| Rytr | 100 | 100 | 99 | 100 | 96 | 91 | 84 | 90 | 97 | 96 | 16 |
| ScaleNut | 100 | 98 | 96 | 70 | 54 | 75 | 78 | 78 | 60 | 61 | 10 |
| SurferSEO AI | 100 | 100 | 100 | 99 | 85 | 90 | 66 | 90 | 58 | 57 | 9 |
| WriteSonic | 100 | 85 | 100 | 90 | 87 | 41 | 25 | 25 | 40 | 0 | 3 |
| Google Gemini | 100 | 100 | 100 | 85 | 97 | 99 | 90 | 65 | 93 | 93 | 27 |
The results are mind-blowing…
Straight off the bat you can see that all AI content was detected with 100% accuracy by Originality.ai.
Sapling and CopyLeaks also caught all the AI content with a high degree of confidence.
Interestingly though:
My five human-written pieces of content were the only ones that passed all of the AI-content detection tools.
They barely topped 20% on the major AI detectors which shows these tools can accurately distinguish between AI and human writing.
Bottom Line:
These AI detectors are only getting better and have kept up with new generative AI models. So if I can detect AI content with publicly available tools, you can bet that Google can as well.
The question is:
Do you want to gamble on the fact that Google won’t correct SEO’s who are abusing AI content again?
For me, the risk far outweighs the reward.
My team and I will continue to produce quality human-written content that provides real value.
I’m not saying that AI content can’t rank today, but I am saying it is an uncontrolled risk that is currently being abused at a huge scale. The second correction is coming, just like it has many times before over the last 20 years.
But for the sake of context, let’s look at how these 2025 results compared with our original AI-detection test in January 2023. Remember, Google nuked a ton of AI sites in March 2024.
Looking at our 2023 results compared to 2025, it’s clear the game of “cat and mouse” has dramatically shifted.
In 2023:
But then, in 2025:
- No AI tool consistently passed detection across multiple tools
- Even the most advanced AI models (GPT-4o, Gemini Flash, Claude Sonnet) are instantly caught
- Detection accuracy has skyrocketed to near-perfect levels
What got me is how one-sided this game now is.
AI generative models have advanced significantly over the last couple of years.
But, AI-content detection has evolved faster.
Remember:
If it’s written by a machine, it can be detected by a machine
And that’s never going to change.
Comparing the results in these two case studies that were just 2 years apart, reinforces my point that using AI content for SEO is a major uncontrolled and unnecessary risk.
These include some of the most recommended AI content tools from even big names in the SEO industry.
Let’s take a more in-depth look at each of them.
ChatGPT is still the most used generative AI tool on the planet, with a 39% market share in the US and a 37% market share in the UK.
Here’s how it performed in our test:
- Model Version: GPT 4o
- Avg. Detection Rate: 85.27%
- Originality’s Detection Rate: 100%
The premise is simple – Ask ChatGPT to write something (or ask a question) and get back a well-worded piece of content in a number of seconds.
Magic, right?
It even includes advanced capabilities such as:
ChatGPT has a free and paid version, which is why so many users have adopted it, but it failed all of our detection testing.
WriteSonic is an AI content marketing platform that helps you plan, write and optimise your SEO content.
They have a suite of tools to help you produce AI content that sounds like you. This includes training your own AI model so it writes just like you.
How did it perform in our test?
These are the results:
- Model Version: WriteSonic 6 Instant Article
- Avg. Detection Rate: 50.82%
- Originality’s Detection Rate: 100%
WriteSonic actually performed the best over every tool we tested in terms of AI content detection.
But that’s still over half the content being detected as AI, putting it into the “fail” category. Originality.ai flagged every piece as AI.
WriteSonic is very focused on content marketing in general.
That means the platform is designed to help you generate:
They also have “PhotoSonic”, which generates AI images.
Keep in mind that AI images are also detectable.
Koala.sh launched in April 2023 with a massive lifetime deal.
Koala was second in terms of AI detection:
- Model Version: Koala & Claude Sonnet 3.5
- Avg. Detection Rate: 59.91%
- Originality’s Detection Rate: 100%
The tool essentially helps you create custom one-click, SEO-optimised AI articles in seconds. All you have to do is:
The big difference is that you can create a custom outline and add custom prompts to each section.
This should (in theory) help you get a very unique content output. But it still wasn’t enough to get anywhere near passing our AI content detection test.
DeepSeek burst onto the generative AI scenes after creating a better AI model than GPT-4o for up to 95% cheaper.
They are a major competitor to ChatGPT.
Their results in our test were:
- Model Version: R1
- Avg. Detection Rate: 63.91%
- Originality’s Detection Rate: 100%
Despite having a lower max output token length that was less than other models, they performed better in the test.
It’s nowhere near close enough to pass AI-content detection, but it’s an interesting aspect of the case study either way.
DeepSeek’s specialisations include:
Their open-source platform gives developers access to create their own AI models and tools.
Article Forge is also primarily designed for long-form content.
It creates 1,500-word articles in less than 60 seconds, including:
You can even publish the content directly to WordPress from the platform.
Article Forge promises quality and unique content. The content quality is subjective, but one thing is for sure…
It’s easily detectable-
- Model Version: Article Forge
- Avg. Detection Rate: 66.18%
- Originality’s Detection Rate: 100%
This is despite them claiming on their site that their articles will “Pass AI Content Detection”.
Regardless of their claim, the test results show their content isn’t unique and is easily detected as AI-written content.
Scalenut is like an end-to-end AI-powered content writing and marketing platform.
What I mean by that is you can use AI to do the:
They have a traffic analyser built into the platform to measure the results. They even have a humaniser to make your content seem like a human wrote it.
But Scalenut content still didn’t pass the AI detection test:
- Model Version: Scalenut
- Avg. Detection Rate: 71.00%
- Originality’s Detection Rate: 100%
Scalenut offers many other SEO AI writing features, including content briefs, keyword planning, SERP analysis and more.
Frase is a powerful tool that started out by helping writers create website content and optimise their content perfectly to rank higher in Google.
It has evolved significantly over the last few years, developing its own AI writer to produce content faster.
They are also part of the Copyrytr group, which has a collection of AI tools including:
This has helped them develop their own AI content generation models faster.
How did the content perform in our test?
Worse than last time:
- Model Version: Frase
- Avg. Detection Rate: 72.18%
- Originality’s Detection Rate: 100%
Frase is a great platform for helping improve and optimise your content. But I would stay far away from the AI writer.
Check out my complete Frase review to learn more about it.
Claude Sonnet 3.5 is a revolutionary AI model.
We used it to create our free AI Google Quality Rater tool because of Claude’s powerful analysis features.
It’s also said to be the best writing model, powering most of the popular article writers available at the moment.
That’s why I was excited to test it out!
But, the AI content was easily detectable:
- Model Version: Sonnet 3.5
- Avg. Detection Rate: 75.27%
- Originality’s Detection Rate: 100%
Claude Sonnet 3.5 is very useful for a lot of different things. It has excellent:
Just don’t use it to generate content.
Jasper has been the market leader in AI content creation for a long time.
They were one of the first tools to be released and have some of the most advanced AI writing features of any tool I tested.
In our last AI content detection test, they were also one of the few tools that could beat AI detectors.
But not anymore:
- Model Version: Jasper
- Avg. Detection Rate: 76.91%
- Originality’s Detection Rate: 100%
Jasper uses its own AI models alongside Open AI (ChatGPT) and Anthropic (Claude).
They’ve become more of a complete marketing platform, allowing you to create brand voice guidelines and build custom workflows for almost any type of writing.
The quality of their writing output is superior to most of the other tools I tested by a long-way.
The platform allows extras like team management, custom knowledge base and art generation.
SurferSEO also started out as an SEO research and content optimisation platform.
They were one of the first tools to develop a one-click AI article writer.
You add your keyword, select your settings, review the AI-generated outline and click generate.
Easy, right?
SurferSEO AI scored 9th overall in our test:
- Model Version: SurferSEO GPT 4o
- Avg. Detection Rate: 77.64%
- Originality’s Detection Rate: 100%
SurferSEO is still an incredible tool that I rate highly and use almost every day!
It has a ton of valuable features like:
… and more to ensure your content is optimised properly.
Just avoid the AI writing features.
Learn how I leverage SurferSEO to rank 1 with my complete SurferSEO review.
Kafkai is an AI content generator that also specialises in competitor analysis.
The unique thing they offer is a proven SEO workflow.
You start by using the Kafkai platform to find easy keywords your competitors are ranking for. Then, you write content to compete for those keywords.
Make sense, right?
You target easy keywords and generate more traffic.
But like every other platform, their AI content is detectable:
- Model Version: Kafkai
- Avg. Detection Rate: 83.27%
- Originality’s Detection Rate: 100%
I like the process they bring to the market. Although the AI content reads well, it was easily detectable by almost every content detector we tested.
Phrasly AI started out as just an AI humaniser.
But they’ve developed a couple of other products, including AI writing.
The biggest differentiator is that Phrasly is simple to use.
My thought is that with a built-in AI humaniser and AI detector, Phrasly would produce content that passed the AI content detection test from the get-go.
That wasn’t the case-
- Model Version: Phrasly A
- Avg. Detection Rate: 83.91%
- Originality’s Detection Rate: 100%
They were in the bottom three of all the tools we tested. The AI content didn’t even pass their own detector.
In saying that, they do currently have the best AI rephrasing tools, and the platform’s simplicity makes it easy to use.
But the AI content is still easily detectable.
There is no doubt that Google Gemini is powerful.
It’s considered to be one of the four big AI models at the moment (along with ChatGPT, Claude, and DeepSeek).
But not when it comes to producing undetectable AI content:
- Model Version: 2.0 Flash
- Avg. Detection Rate: 86.36%
- Max Token Length: 8,192
Like Calude and ChatGPT, there are a ton of other great use cases for it.
Google Gemini 2.0 Flash is good at anything related to reasoning and problem-solving. It also has advanced coding capabilities and handles large, complex prompts well.
Rytr is primarily an AI writing assistant that is best at coming up with different angles for copywriters, marketers and entrepreneurs.
Rytr is one of the most affordable AI writing tools with a cost-effective unlimited content writing plan.
This has made it extremely popular over the last couple of years.
But it scored the worst of every tool we tested:
- Model Version: Rytr
- Avg. Detection Rate: 87.91%
- Originality’s Detection Rate: 100%
Rytr also didn’t do well in our first AI content detection test in 2023. And it has continued down that path.
Where Rytr really stands out is marketing copywriting. They offer very attractive pricing and a simple platform to generate copy quickly.
You can generate in 30+ languages, including tone adjustments and writing style.
But I would stay far away from any SEO content generated by Ryrt.
Here’s the list of AI Content Detection Tools we used:
I’ve used and tested a lot of these tools over the years, so there is quite a bit for us to unpack here.
But based on the results above:
🏆 Best AI Detection Tools
What about the best AI detection tools?
These are the three winners from our test results:
- Originality.ai: Clearly the best overall, catching all the AI-generated content with ease
- Sapling: Came in a very close second with high AI detection rates
- CopyLeaks: Delivered excellent AI detection rates and did the best job at identifying my own content human-written
Personally, I will continue to use Origniantly.ai in the future, with CopyLeaks as a backup and second opinion.
You can learn more about each AI content detection tool used in the test below:
Originality.ai is the OG AI content detection tool.
They’ve got the most consistent results and have only continued to improve over the years.
They were the only tool on the list that essentially detected every piece of content as AI, with an average detection rate of 99.94% from all tests.
That’s incredible!
Originality.ai is also one the only tools that detects humanised and paraphrased content. That’s why they made our best AI SEO tools list.
The interesting part is that Originality.ai did detect my human-written content at an average of 27% AI from all tests. So, there is still some room for improvement.
But, Originality is good at what it does and is continuously being developed to stay up to date with modern AI writers.
It’s the one I trust moving forward!
Want to learn more about this tool? Read my full Originality.ai review.
Sapling’s user interface is basic.
But don’t let that fool you…
The team behind Sapling have built an accurate AI content detector designed to detect even the latest AI models.
Sapling scored an average detection rate of 97.21% from all articles and even handled my human-written content much better than Originality.
Sapling is simple, easy to use and most importantly – Accurate.
Copyleaks has more of an education focus.
They started out detecting AI content that students submit for university and school assignments.
Because of the way they trained their AI detection model, you get far fewer false positives than other tools. And our test results showed the same…
Copyleaks was one of the only AI detectors that scored my human content as 0% AI. And to top that off, they had an average AI detection rate of 95.30%.
This cements Copyleaks as one of the most accurate tools for both Human and AI content. Impressive!
GPTZero is an advanced AI detector that was inspired to stop ChatGPT.
It uses advanced variables to track AI models and detects their digital fingerprints.
GPTZero had an average AI detection rate of 89.40% which was far better than the results back in 2023.
They are currently developing their technology for educators to stop students from taking advantage of AI for college and school assessments.
Quillbot AI detection technology has developed significantly over the last couple of years.
They have become one of the most well-known AI detectors.
In my last test, I received a bunch of emails and messages asking me to test their detector. That’s why I added them to the mix this time.
Quillbot had an average AI detection rate of 80.97%, placing it just inside the top 5.
They’re popular because of their suite of tools, which include paraphrasers, grammar checkers, plagiarism checkers, translators, and more.
Winston AI is more than just a content detector…
You can content to the platform and get a bunch of insights including your readability.
Winston AI had an average AI detection rate of 76.91% in our test.
Their user interface is easy to use, and the tool is robust. They’re also working on developing their models for education use.
BrandWell detects AI by looking for common patterns used in AI-generated content and then forecasts probable word choices based on individual models.
It colour codes every sentence on the page, highlighting the likelihood of the content being AI-generated.
They scored an average AI detection rate of 71.64% and definitely worked better against some tools more than others.
BrandWell’s goal is to create an AI detection algorithm that can even detect edited AI content accurately.
I agree, that’s the future!
TurnItIn, as the name suggests, has a strong academic focus.
They scored a solid average AI detection rate of 69.64% from all articles.
It’s clear that TurnItIn works better in the academic world. They even have a dashboard that allows for better analysis of AI-written academic papers.
ZeroGPT is all about speed.
Their main point of difference is fast AI content checking and bulk uploads.
As for the detection rate?
It was a lower-than-expected 61.10% average AI detection rate.
ZeroGPT is affordable and has a straightforward, easy-to-use platform layout. There is also a free version, but the site is littered with display ads.
As I mentioned before, Phrasly is better at humanising AI content than actually detecting (or writing) it.
And the results show. Phrasly scored a low 60.67% average AI detection rate for their score.
It placed it comfortably in the bottom 3 of all the AI content detectors we tested.
Last and very much least, was Writer.
I know that not all AI content detectors are built the same. But Writer really proved this point with a terrible average AI detection rate of just 14.77%.
That is incredibly low and essentially means that Writer passed most of the AI-generated content.
Writer has created a bunch of other excellent apps and features. But the AI content detector isn’t one of them.
Just spend 15 minutes reading through a Reddit forum, and you will see a multitude of people claiming that humanisers are enough to beat AI content detectors.
But the reality is different…
Humanisers aren’t guaranteed to work primarily because AI’s still producing the content. It might slightly lower the detection rate, but you’ll likely still get caught out.
Plus, tools like Origniality.ai are constantly updating their detection models to catch humanised content.
If that’s not enough for you, there are a few more reasons to avoid them…
The goal of a humaniser is to make the AI content “undetectable”.
How do they work?
The goal is to essentially add nuances that make it sound more “human”.
The problem is that this adds extra words into the sentence, disrupting the flow and affecting the readability.
You have to ask yourself…
Is humanising AI content really providing value to your readers?
And that’s not all.
Many humanisers resort to tricks like messing with the formatting, adding double spaces or replacing letters with unique characters that kind of look the same to the naked eye.
I mean, look at this result I had using a humaniser:
This is essentially what we used to call auto spinning in 2012, and spinning things automatically instead of manually wasn’t a recommend practice back then either.
The simple fact is that:
If it’s written by a machine, it can be detected by a machine!
The truth is that humanisers are still playing the game of cat and mouse. You might fool basic detectors, but you’ll likely get caught in the end.
They aren’t a foolproof solution for AI content and are still high-risk to use for your website SEO.
Can Google detect content written by AI content creators?
Short answer – Yes because if we can do it with publically available tools, so can Google who have invested more in AI than any other tech company.
And they will continue to invest a massive $75 billion more in 2025.
Not to mention the fact Google published a paper in 2020 showing how they can use text generation models to detect low quality content.
A simillar test by Jon Gillham, comprehensively showed that AI content detectors could easily detect AI-written content as did Surfer.
It’s also likely that email spam filters (the biggest is opearated by Google) and social media networks will start to integrate AI content checkers in the future.
This could mean that your emails go directly to spam or posts on popular social media sites get limited reach.
So are AI based content generators valuable at all?
Yes, if you use them properly.
AI generators are great for:
…for human writers.
From my testing, it’s clear to me that the best AI SEO tools can come up with some amazing ideas and angles for content creation.
But when it comes to actual content writing for a website – stay away!
If Google decides to penalise sites using AI content in the future, it could completely destroy an entire website.
Don’t get caught up in the hype.
Protect your site and avoid using AI writers for website content or anything to do with SEO. We won’t be using it to create social updates or emails either!
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Very eye opening article! The way you explained the risks of relying blindly on AI-generated content in 2025 makes a lot of sense. Quality and authenticity are more important than ever, especially when trust is at stake. It reminded me that in business whether it’s digital marketing or something totally different like termites control services people value genuine effort and reliable solutions over shortcuts. Thanks for breaking this down so clearly!