12 Best AI Detectors in 2025: From Over 180 Tests (Updated)

My Overall Pick

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Originality AI

Originality.AI is the best overall AI detector with the highest accuracy.

Try Originality AI

Runner Up

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Winston AI

Winston AI is the runner-up AI detector with features like OCR.

Try Winston AI

Best Free

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Passed AI

Passed AI offers an excellent 100% free AI detector Chrome plugin.

Try Passed AI

You were probably thinking, “Can Google detect AI content?” right?

With the rise of AI writing software, it’s only a matter of time before search engines catch on.

Why?

Because AI-generated content lacks creativity, personality, context, and factual accuracy most of the time.

Over 63% of professionals struggle with bias and accuracy using it.

And that isn’t valuable to real human readers.

Do you really want to risk it?

I ran over 180 accuracy tests and ranked the best AI detectors to:

• Avoid spam detection
• Increase rankings
• Improve user experience

Check the results.

What Is the Best AI Detector?

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Here are my top 12 picks for the best AI detectors.

1. Originality AI

Best Overall AI Detector

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Originality.AI is an AI-detection and plagiarism checker tool targeted toward serious content publishers.

My test shows they are currently the most accurate AI detector with an accuracy score of 93.3%.

Meaning…

They accurately predicted 14 out of the 15 test samples I ran.

Note: The results are based on my independent tests. Yours might vary.

It also offers very generous team features, API integrations, and a pay-as-you-go payment structure.

Key Features

Pricing

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Originality AI currently has three pricing models.

• Pay as you go: Buy in 3,000 credit batches for $30
• Pro: $14.95 monthly for 2,000 credits (or $12.95 on the annual plan)
• Enterprise: $179 monthly for 15,000 credits (or $136.58 on the annual plan)

Pretty reasonable pricing for 2025.

2. Winston AI

Best Originality Alternative

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Winston AI just missed the top spot with an accuracy score of 86.7%.

It’s one of the newer AI content detection tools. But packed with a ton of unique features that most of the detectors on this list lack.

Originality AI currently wins in accuracy by just a margin.

They are extremely similar…

But Winston AI can detect AI images with Optical Character Recognition (OCR) technology. Originality can’t.

I use both in my content creation process because you can’t just rely on one tool.

You wouldn’t trust only one doctor’s diagnosis if you had a critical illness.

Key Features

Pricing

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Winston AI offers the following pricing plans:

• FREE: $0 per month
• GROWTH: $14 per month if paid annually. $18 if monthly.
• CUSTOM: Contact their team

Start your 7-day FREE Trial with 2000 words with my link below. No credit card is required.

3. Passed AI

Best AI Content Detector Chrome Extension for Academic Institutions

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Passed.AI is the ultimate solution for educators to prove that submitted work is either student-written or AI-generated. 

It leverages Originality.AI‘s accurate AI detection algorithms API and other leading NLP models to detect plagiarism and cheating.

Passed.AI ensures the highest level of AI detection through an entire document audit trail to decipher the exact activity used to create the content.

No other tool can match its enforceability.

Key Features

Pricing

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Passed AI offers the following pricing plans:

Start your 14-day free trial now. Get a full refund within this period if you’re unsatisfied.

4. Sapling

Best Free AI Content Detector

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Sapling is an AI messaging assistant for Customer-Facing Teams. 

Still, the team has developed a free AI content detector that is surprisingly quite good and up-to-date.

Key Features

Pricing

Sapling’s AI Content Detector is entirely FREE.

5. AI Detector Pro

Best AI Detection Suite

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Another AI detection tool?

Wait… You’re gonna like this one.

AI Detector Pro doesn’t just scan for AI-generated content, but it’s an entire suite equipped with a whole bunch of other useful tools and utilities.

Forget about jumping between other sites before publishing.

Just do it all in one dashboard.

Key Features

Pricing

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AI Detector Pros has these plans:

• FREE: $0
• BASIC: $13.99 monthly
• UNLIMITED: $24.99 monthly

Use the code and sign up using my link below for 50% off.

6. GPTZero

Best for Detecting AI Content in Academia Niches

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Worried about AI-generated text slipping into academic work?

GPTZero provides a fast way to spot fake content and highlight AI-written sentences.

Edward Tian, a Princeton student, created GPTZero, now trusted by over 1 million users, as a reliable AI detector for maintaining academic integrity.

It was trained on a large corpus of human-written text that spans student-written articles, news articles, and question-and-answer datasets across multiple disciplines in the sciences and humanities.

Key Features

Pricing

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GPTZero offers the following pricing plans:

7. Crossplag

Best for Academic Integrity

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Like Originality.AI, Crossplag has a plagiarism checker and AI content detection features.

Originality operates on a credit system, while Crossplag is free to use.

The team seems to be positioning the tool toward academic integrity and enterprise usage.

Key Features

Pricing

Crossplag’s AI detection tool is FREE to use.

8. Writer

Best for API Integration

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From their name, you can guess that Writer is an AI writer tool that helps you…well, write content – duh.

To stay competitive, it’s also reasonable to expect they would have an AI content detection tool for their users to check for AI-generated text.

And similar to other tools, theirs also show a content score as a percentage.

Key Features

Pricing

Writer’s AI Content Detector is entirely FREE.

9. Content at Scale

Best Built-in AI Detector With Content Generation

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Content at Scale is one of the new guys on the block offering an excellent 100% free AI detector.

It can check for AI-generated content made by GPT-4.1, ChatGPT, and other AI models with decent accuracy.

Key Features

Pricing

Content at Scale’s AI detection tool is completely FREE.

10. Kazan SEO

Best for Detecting Bulk AI Content Through URL

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Kazan SEO is an entire SEO toolkit that includes an AI content detection tool as one of them.

Outside of AI detection, they have a content optimizer, text extractor, keyword clustering tool, and many other SEO tools.

Key Features

Pricing

Kazan SEO AI Content Detector is entirely FREE.

How I Test AI Detectors?

In this article, I have tested 12 different AI detector tools using the same texts and scoring system. Some of these tools are free, while others come with paid plans.

1. Performance Metrics

I used the following metrics to summarize the performance of an AI detector tool:

• True positive (TP): AI-written text is predicted by the tool as fake.
• True negative (TN): Human-written text is predicted by the tool as human.
• False positive (FP): Human-written text is predicted by the tool as fake or AI-made.
• False negative (FN): AI-written text is predicted by the tool as human.

2. Diverse Dataset

To make the comparison fair, I used different types of texts that cover different topics. Two topics are technical, while the remaining three are general blog articles. 

These are the texts used:

• Blog article titled 10 Kinds of Phobias You Might Not Heard Of
• Blog article titled How Fast Does Pothos Grow?
• Blog article titled What Are the Advantages and Disadvantages of WiFi for Home Automation?
• Journal paper titled Development of A Low-Cost Chlorophyll Meter
• Introduction to a thesis paper titled Wireless Sensor Network Application in Precision Agriculture

For the AI-generated texts, I used GPT-4o and used the same prompt. For instance, I asked chatGPT to “write content about growing Pothos plants and tips.”

However, I added additional prompts for the technical papers to produce the desired content. 

For example, “include in the abstract that the prototype’s coefficient of determination is 0.8276 when compared with results from SPAD-502 and spectrophotometer.”

3. Training and Testing

Each of the 5 texts is between 1200 to 1800 words. To test the performance of the AI detector tools, I created additional variations of each text and categorized them as follows:

• 100% human
• 100% chatGPT 3.5
• 50% human, 50% chatGPT

Overall, I have tested a total of 15 text samples.

4. Accuracy Scoring

The accuracy score is defined as the total number of correct predictions divided by the total number of data.

The following formula is as follows:

Accuracy score = (TP + TN)/ total number of texts tested

Where TP is the total number of true positives, and TN is the total number of true negatives.

For example, if a text has a TP of 9 and TN of 4, then it would be computed as:

Accuracy score = (9 + 4)/ 15 = 0.8666 or 86.7%

5. Rating score

Each AI detector tool is initially assigned a perfect score of 5 to get the rating score. Whenever it outputs a false positive or false negative, the score is subtracted with 0.3.

What Are AI Detectors?

AI Detectors (AI Content Detectors or AI Text Detectors) are software tools that use artificial intelligence to determine if a piece of text content is written by a human or another AI tool like ChatGPT. They usually show an accuracy score to illustrate their confidence in whether AI partially or entirely wrote it.

What Is the Best Free AI Detector?

The best free AI content detector is Sapling which had an accuracy score of 66.7% based on my testing.

It was developed by former researchers at the University of California Berkley, Stanard, and Google.

Another honorable mention is Paraphrasingtool.ai.

It’s able to detect GPT-4 content with decent accuracy given that it’s a free tool.

Are AI Detection Tools Worth It?

You don’t want to create content blindly with AI only to be penalized by Google in the future.

AI detection tools are also worth using to ensure AI content is humanized.

I’ve worked with many freelance writers, and it’s my first line of defense against their lies.

Some blatantly use AI writers even when they tell you they don’t.

And besides, most of the tools on this list are free, so there is no excuse not to use them.

Why Is It Important To Detect AI Content?

By detecting AI content, we can ensure that the information we view and interact with is authentic and accurate.

Here are other practical applications:

• Preventing Google from flagging AI content as spam.
• Preventing employers from getting ripped off by writers who say their content is original.
• Ensure that the writing makes sense and is logical.
• It keeps the human’s creative juices flowing and prevents laziness.

What Are the Limitations of AI Detection Tools?

The limitations of AI Detection Tools will always be the data it’s fed and trained on.

Because if the training data is not a good representation of the type of content the tool will be analyzing, then the results are likely to be inaccurate.

Here are more limitations:

• AI tools can only understand patterns and derive conclusions from them. They can have no concept of context, leading to false positives and negatives.
• They may struggle to understand and detect more nuanced or subtle forms of content, such as sarcasm, irony, or satire.
• Not all training data is publicly available, but sometimes it could be illegally scraped online, raising privacy, ethical or legal issues.
• Definitely not a “let Jesus take the wheel” solution, so human oversight is still needed to review flagged content and make final decisions.
• As AI systems are based on machine learning, they require continuous updates and maintenance to adapt to the changing nature of the content, which may require additional cost and effort.

Read my article How Does AI Detection Work if you want to find out more.

Best AI Detector Reddit comments

The thread reveals significant skepticism and inconsistency in opinions regarding the reliability of AI content detectors. Many users argue that no current detector is foolproof, while others advocate for specific tools—even if only with caveats.

Key points include:

• Widespread Skepticism:
  Several commenters assert that none of the detectors can be trusted. One user bluntly states that the detectors are “literally an AI just pulling nonsense out of its ass,” and that they would not stand up in court—reflecting a broader sentiment that current technology is unreliable.
• Mixed Reviews on Specific Tools:
  Despite the overall doubt, certain detectors receive intermittent praise. Some users point to ZeroGPT as the most accurate tool they’ve used, while others share contradictory experiences (e.g., having GPT-generated content misclassified as “100% human”).
  Similarly, Undetectable.ai is mentioned favorably by a couple of users for bundling multiple detectors into one free package, though opinions vary.
• Challenges of Detection:
  Many discuss how subtle aspects like tone, phrasing, and even the vocabulary level might tip off human evaluators. Yet, as one commenter notes, when text is heavily rephrased or “simplified,” it might slip past even the best detectors. This leads to the general conclusion that while AI detectors might offer a hint, they are far from definitive.

Best AI Content Detectors (FAQs)

To Sum up

Alright, that’s a wrap.

No matter what industry you are in, you can stand to benefit from AI writing tools.

However, you can’t publish AI-generated content without adding a human touch.

Using AI content detection tools, ensure you don’t take Google’s or any other search engine’s policies for granted.

Checking before posting will ensure that your AI articles are spam free and safe from future core updates from Google.

I hope this helps you, and remember to share this blog post with others.

Leave a comment below if you have other exciting things to add.