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Best AI Detection Tools

8 Best AI Detection Tools [So You Don’t Get Penalized]

Google can detect AI content? Can you?

Using one of these AI detection tools can help you grasp how “human-like” your AI-generated content is and what edits you can make before publishing and risking Google detecting your AI content.

Best AI Detector

ContentatScale Logo

Content at Scale

  • Detector is part of our favorite AI writing tool for generating long blog posts
  • Includes an AI image detector
  • Works with ChatGPT, GPT4, Bard, Claude, & More
  • Both free & paid versions available

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Best AI Rewriter

Undetectable AI Logo


  • Detector is part of a simple rephrasing tool to quickly pass as human output
  • Detects AI by cross-checking 8 other detectors
  • Works with ChatGPT, GPT4, Bard, Claude, & More
  • Both free & paid versions available

Learn More

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How Does Google Detect AI Content Video

AI Detection Tools Comparison

Detector Name

Our Rating

Top Feature

Best for

Content at Scale
AI image detector, works with various AI modelsAI checker + blog post generator
AI prediction map and readability scoreEducational institutions and students
Straightforward AI content detectorGeneral content creation and checking
AI and plagiarism checkerSEO agencies and content marketers
Kazan SEO
All-in-one SEO AI detection toolComprehensive SEO analysis
Aggregates scores from 8 other detectorsUsers needing quick rephrasing tools
Hugging Face
Open-source AI communityAI researchers and hobbyists
Color-codes each word in a postTech enthusiasts and academics

1. Content at Scale

Best AI Checker + Blog Post Generator – 4.5/5 Rating

Content at Scale Logo Main

4.5 of 5 Stars

The new feature added to our favorite AI writer, Content at Scale's AI Detector, is topping our list.

We love this detector because it has the ability to detect when content comes from ChatGPT, GPT4, Bard, Claude, or any other AI model within moments.

You can generate your content using Content at Scale’s AI writing service and check for its human-like quality using the built-in detector before posting.

It not only gives you a simple score out of 100 on how human the content is and how likely it is to be detected by Google as artificial, but it also breaks that score down into key elements like predictability, probability, and pattern, giving users more insight into what about their content seems “AI.”

Another new feature that Content at Scale recently added that we’re excited about is the sentence-by-sentence breakdown. The detector will highlight each sentence of content in a color that corresponds to its detectability, so you can fix the sentences that appear to be AI-written and not worry about sentences that work.

A bonus: most of the Content at Scale content ran through it earns a high “Human Content Score,” so you have to do less work on editing it.

Content at Scale Best Features:

  • Includes an AI image detector 
  • Works across several AI models
  • Sentence-by-Sentence breakdown 

Content at Scale Limitations:

  • Must pay a monthly subscription for Pro features

Content at Scale Ratings & Reviews:

Content at Scale AI Detector Pro

Content at Scale has added a Pro version of their AI Detector. For $49 monthly, you’re now able to get scans of up to 50,000 characters in one scan—that’s between 7,000 and 12,000 words—and a rewriting tool. We love this upgrade.

Content at Scale already produces undetectable content, so having an AI rewriter/paraphraser onboard that produces quality content saves me from having to go elsewhere for my rewrites and still having to do major edits because that output isn’t great.

The new addition to Content at Scale’s suite of tools makes it more of a timesaver and a one-stop shop for content creators.

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2. Winston

Best for educational institutions and students – 4.5/5 Rating

Winston Ai Logo Main

4.5 of 5 Stars

Winston positions itself as an AI detection tool for educational content. It’s a great solution for students and teachers but it also works well for other content creators.

Copy and paste content or upload a document and receive the human probability score in seconds.

With an AI prediction map, Winston shows you the most AI-sounding areas to address in your content. It also provides a readability score, including the approximate grade level the content is written.

Furthermore, with the Advanced and Elite plans, you can also run a plagiarism check right on their easy-to-use platform.

Winston Best Features:

  • Easy-to-use dashboard
  • Showcases percentage likelihood of AI content 
  • Supports several file types including .png, .jpg, and docx files
  • Gives you a readability score as well 

Winston Limitations:

  • Supports fewer languages than other tools 
  • Could improve the reporting option

Winston Ratings & Reviews:

4.0/5 on Capterra (under 5 reviews)

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3. Writer

Best for general content checking – 4.3/5 RatingWriter Logo Main

4.5 of 5 Stars

With a straightforward name, Writer is a leader in… well, written content creation.

It also has an easy-to-use AI content detector to make it easy for users to check their AI-generated content before sending it out into the world.

Similarly to Content at Scale’s AI detector, Writer’s shows a detection score in percentage.

If you need help, they have a dedicated customer support team as well.

Writer Best Features:

  • Straightforward and simple to use
  • Has a dedicated customer support team
  • Provides percentage-based score

Writer Limitations:

  • Does not offer as detailed of an analysis as other tools 
  • Lacks the advanced content features other tools offer

Writer Ratings & Reviews:

  • No customer reviews

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4. Originality.AI

Best for SEO agencies and content marketers – 4.2/5 Rating

Originality Ai Logo Main

4 of 5 Stars

Checking for both AI and plagiarism, Originality.AI puts the user in control of their content’s originality.

Since AI writers largely pull their information directly from other posts on the internet, the risk of plagiarism can be pretty high. With Originality.AI, not only can site owners gain insight into how human-like their content is, but they can also see how original the content itself is.

By doing both at the same time, site owners and content creators can save time and money and mitigate the risk of Google detecting any machine-created content.

Check out our review.

Originality Top Features:

  • Includes plagiarism checker
  • Ideal for website owners and content creators
  • Can add coworkers/collaborators to streamline teamwork

Originality Limitations:

  • Pay-as-you-go model limits your options
  • High reports of inaccuracies 

Originality Ratings & Reviews:

  • 2.9/5 on Product Hunt (over 20 reviews)

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5. Kazan SEO

Best for AI detection with comprehensive SEO analysis – 4.1/5 Rating

Kazan SEO Website Banner

4 of 5 Stars

For an all-in-one SEO AI detection tool, check out Kazan SEO.

This neat toolkit has multiple features outside of AI detection, including a content generator, a tool for discovering and researching keywords, URL text extraction for SEO analysis, and co-relational content optimization.

If you need more than just an AI checker, we recommend Kazan SEO for its wide variety of SEO tools.

Kazan SEO Best Features:

  • All-in-one SEO and AI detection tool
  • Several robust features for content generation 

Kazan SEO Limitations:

  • Better for those needing SEO tools, but not ideal for simple AI-detecting

Kazan SEO Ratings & Reviews:

  • No customer ratings

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6. Undetectable.AI

Best AI Checker + Rewriter – 4.0/5 Rating

Undetectable AI Logo Main

4 of 5 Stars is an all-in-one AI writer, paraphrase, and, you guessed it, detector.

What sets this AI writer’s detector apart is that it aggregates scores from 8 other AI detectors. This means you can see AI detection likelihood scores from GPTZero, OpenAI, Writer, Crossplag, Copyleaks, Sapling, Content at Scale, and ZeroGPT, all in one place. Because of this, the detector is pretty good at detecting AI content.

The only drawback to this detector is that it won’t highlight specific parts of text that seem less human, so you can hone in on what to edit. But when you consider that the same software also paraphrases and writes original content, Undetectable AI is worth a try.

Undetectable.AI Top Features:

  • Aggregates scores from 8 other detectors
  • Includes writing and paraphrasing features
  • Good accuracy in detecting AI content

Undetectable.AI Limitations:

  • Does not highlight specific areas for robotic content 

Undetectable.AI Ratings & Reviews:

  • 5/5 on Product Hunt (under 10 reviews) and G2 (under 5 reviews)

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7. Hugging Face

Best for AI researchers and hobbyists – 4.0/5 Rating

HuggingFace Logo Main

4 of 5 Stars

The “home of machine learning,” HuggingFace is used by over 5,000 organizations, including Grammarly and Google AI.

Though it’s an open-source AI community where folks can share ideas, the site also has a free AI detection tool.

All a user needs to do is copy/paste their content into the box, and it will show the user where it ranks on a “fake” to “real” scale.

Results get more accurate the more content the tool is fed, so this one may be better for folks who are testing longer AI-written content.

They also have a good AI image detector.

Hugging Face Best Features:

  • Ranks content on a scale of “fake” to real
  • Ideal for longer AI content, as the tool learns with more content 
  • Based on an open-source AI community 
  • Used by top organizations including Grammarly and Google AI

Hugging Face Limitations:

  • May not work well with short content 
  • Does not provide a clear percentage score or highlight areas

Hugging Face Ratings & Reviews:

  • No customer reviews are available 

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Best for tech enthusiasts and academics – 3.8/5 RatingGLTR Website Banner

4 of 5 Stars

Giant Language Model Test Room (GLTR for short) is a detection tool that uses “a suite of baseline statistical methods that can detect generation artifacts across common sampling schemes.”

This was created by a team from MIT-IBM Watson AI lab and HarvardNLP using the GPT-2 language model to differentiate between real and AI-created content.

GLTR essentially color-codes each word in a post to detect how likely that word is to appear in that position in a sentence.

For instance, a word that ranks within the most likely words is highlighted in green (top 10), yellow (top 100), red (top 1,000), and the rest of the words in purple.

GLTR Best Features

  • Color codes each word in your text
  • Created by an advanced technical team
  • Works best for GPT-2

GLTR Limitations

  • Not as efficient for newer technologies
  • Not as easy to interpret the results 

GLTR Ratings & Reviews

  • No user reviews

Learn More

Free AI Detection Tools

Free AI Detection Tools

To fly under Google’s radar, many companies have launched free AI detection tools.

These tools are designed to search through written content, looking for phrases that are organized in a strange or overly predictable way.

These tools then calculate how “human” the content seems, giving it a score that reflects how natural and human-made the content is.

A few free AI detection tools include:

Here are the best free tools to check content generated from ChatGPT.

How To Choose An AI Detection Tool

How to Choose Ai Detection Tool

With so many free and premium AI tools around, picking the best one can seem overwhelming. You need a tool that offers the features you need without overcomplicating things. 

Here are the top qualities to look for in an AI detector:

  • Supports multiple AI models including GPT-3, GPT-4, Bard, Claude, etc. 
  • As accurate as possible (it’s not much good if it gives false negatives or positives!)
  • Supports small and large data items without disrupting accuracy too much 
  • Customizable analysis process to help you focus on the areas you need to most
  • Quality reporting options, especially highlighting words or sentences that appear robotic 
  • Works well on numerous platforms and devices 

AI Detector Tool Accuracy

AI Detector Tool Accuracy

How Accurate Are AI Content Detectors?

Since all of this is so new and Google hasn’t communicated exactly how they detect AI-written content, there is no way for an AI detector to be 100% accurate.

They will give you a score (typically out of 100) of how “human” the content seems and indicate whether or not it is likely to be detected as AI-written content.

This number is a great jumping-off point to get an idea of how much editing needs to be done, but getting a human set of eyes on it is always a good idea to make necessary adjustments for the best content possible.

What Is the Most Accurate AI Checker?

Winston.AI stands out as the most accurate of AI detectors, specifically designed to discern between content written by humans and those generated by AI.

It is renowned for its precision, claiming a remarkable 99% accuracy in detecting content produced by models like ChatGPT, GPT-4, and Bard, according to its internal testing results.

This tool is meticulously crafted to fulfill its core purpose: to distinguish human-written text from AI-written counterparts effectively.

It's not just about identifying AI-generated content but about the reliability and assurance it provides in doing so, making it the preferred choice for those who seek uncompromised accuracy and reliability.

AI Content Detection Tools – Accuracy Score Comparison Table

We generated text through AI for our prompts and ran the same text for each detector tool.

Here are the results:

AI Detector Tool


Content at Scale32% (AI) - 68% (Human)
Originality.AI99% (AI) - 1% (Human)
Winston100% (AI) - 0% (Human)
Hugging Face98.54% (AI) - 1.47% (Human)
GLTRProbability given - no score
Kazan SEO98.53% (AI) - 1.47% (Human)
Writer0% (AI) - 100% (Human)

As you can see in the table above, there’s a wide range of scores for the same generated content. The one that stood out was Writer had a 0% AI score, which I didn’t expect. Originality and Winston seems to be the hardest one to pass, while Content at Scale seems to be a bit more lenient and offers a bit more insight on how to optimize.

However, scores may vary even more depending on the prompt, so our recommendation is to pick one tool and stick with it. And, of course, it’s always best to have a human editor and proofreader review the content, regardless of the human score output.

How Reliable Are AI Content Detectors?

How Reliable Are AI Content Detectors

AI detectors are becoming more reliable, but they are still far from perfect.

You can put the same paragraph into every AI detector on this list and get wildly different results from each, showing that the technology hasn’t advanced enough to be 100% reliable.

With Google and AI writers like ChatGPT constantly switching things up, it’s nearly impossible for current AI detectors to catch everything.

For this reason, we suggest always, ALWAYS, getting a human editor to look over any content before publication. Human eyes can catch things like machines can’t, plus they’re essential for making AI-written content sound human.

How to Fact-Check AI-Generated Content

How to Fact Check AI Content

An important step in preparing AI-written content for posting is fact-checking.

AI writers just pull information from sources all over the internet without discernment, meaning it’s easy for false information to end up in your AI-written content.

Allowing an editor to give AI-written content a look is important.

Fact-checking can be as easy as looking up any statistics and claims made within the content and cross-checking them with credible information sources.

How Do AI Detection Tools Work?

How Do AI Detection Tools Work

AI detection tools work by using a language model similar to the ones used by Google to predict likelihood of certain words and phrases in content. Using this judgement, it is able to give users a score on how “human-like” the content will appear in Google’s eyes.

These tools can help site owners who publish content use AI writers to produce a higher volume of content without risking penalization from Google.

Are AI Detection Tools Worth It?

Since so many AI detection tools are available for free, they are absolutely worth it to ensure that any AI content created will pass under Google’s radar and have the opportunity to rank high in search.

Google and AI-Generated Content

Google and AI Generated Content

The reason for all of these detection tools is Google’s relationship with AI.

It’s complicated.

According to the big guy itself, Google claims to “reward original, high-quality content however it is produced.” So, using an AI writer won’t automatically tank your SEO. 

But (and it’s a big one), if the AI tool generates low-value or poorly written content, it won’t meet Google’s quality criteria. That means, if they can tell it was clearly written by a robot, chances are it’s not good enough quality. 

The key is to provide the best value to Google’s users, which you won’t do if content is repetitive, cumbersome, or just poorly written. That’s why the best bet is to ensure you edit and humanize content until it can pass the top AI detectors. 

To learn more about how to actually us AI for writing, check out our list of the best AI writing courses >>

Best AI Detector

ContentatScale Logo

Content at Scale

  • Detector is part of our favorite AI writing tool for generating long blog posts
  • Includes an AI image detector
  • Works with ChatGPT, GPT4, Bard, Claude, & More
  • Both free & paid versions available

Learn More

Best AI Rewriter

Undetectable AI Logo


  • Detector is part of a simple rephrasing tool to quickly pass as human output
  • Detects AI by cross-checking 8 other detectors
  • Works with ChatGPT, GPT4, Bard, Claude, & More
  • Both free & paid versions available

Learn More

Frequently Asked Questions

What is the best free AI checker?

Content at Scale stands is the best free tool for identifying AI-generated content. Its accuracy and ease of use make it a go-to choice for many seeking a reliable AI checker without the price tag.

Should I use an AI checking tool?

Yes, you should use an AI-checking tool any time you post AI-generated content. Ensuring your content is unique and not machine-generated can help maintain its search ranking and avoid penalties. By checking your content with such a tool, you safeguard its visibility and relevance in search results.

Can AI writing be detected?

AI-generated writing can be detected, and search engines like Google have algorithms in place to identify such content. Ensuring originality and human touch in your content is vital to maintain its credibility. Using AI responsibly and checking its output can help avoid potential penalties by search engines

Will I get penalized on Google for AI-generated content?

Using AI-generated content can lead to penalties on Google. The search engine prioritizes original, high-quality content, and if it detects machine-generated articles, your site's ranking may suffer. That is why it's essential to ensure content authenticity and quality to maintain your site's position in the search results.

What is an AI content detector?

An AI content detector is a tool that scans AI-written content for predictability, giving users an estimate of how likely the content is to be detected by Google.

Our Favorite AI Detection Tool

ContentAtScale Logo

Our Rating: 4.5/5

Read Our Review


What Content at Scale Does Best:


Sentence by sentence breakdown - highlights what is detected as AI


Detects from different language models (GPT4, Bard, Claude, etc.)


Pro plan ($49/month) lets you rewrite to pass detection

Try it for Free