30 Best AI Detectors for ChatGPT AI Writing & More

AI writing is still in its infancy, but it’s only going to become more prevalent as a wider range of people use tools such as ChatGPT to generate text. AI detectors help spot AI generated writing, but when there are so many options, it can be hard to distinguish the best from the bad.

We have created a list of the 30 best AI detector tools and tested them for accuracy.

Here is our list of the AI detectors that we reviewed and tested:

1. Pangram Labs

Pangram Labs Dashboard

Free – Yes - You have to sign up to access 5 free scans per day

Paid – Yes

Pricing (Based on lowest per month cost) - $15 gets you up to 600 AI scans per month (Documents over 1000 words use 1 credit per 1000 words)

Test Scores:

AI Generated Text Pass Rate – 9/9 (100%)

Human Written Text Pass Rate – 3/3 (100%)

Developed by a team of AI researchers from Stanford, Tesla and Google, this tool was made with the sole purpose of detecting AI text. It’s kept up to date as new models are brought out by the various AI tools and presents a near-zero false positive rate. It supports over 20 languages and has Chrome and Canvas extensions too.

The test results reflect how confident we are in our tool, passing all tests with full accuracy.

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2. Quillbot

Free – Yes (1,200 words)

Paid – Yes (unlimited words)

Pricing (Based on lowest per month cost) – $19.95

Test Scores:

AI Generated Text Pass Rate – 4/9 (44%)

Human Written Text Pass Rate – 3/3 (100%)

Founded in 2017, Quillbot was created to help students learning English improve their writing. They have expanded their tools since then to include an AI detector. It states that it can work with a multitude of languages including English, French, German, Spanish and Dutch (we have only tested English).

Once you have put in your text, it generates four scores ‘AI-generated’, ‘AI-generated & AI-refined’, and ‘Human-written & ‘AI-refined’, and ‘Human-written’. This will tell you what the tool makes of your text.

The tool performed well when testing our human-written text, but it didn’t do as well on detecting AI generated text. It detected all of our Gemini generated writing but failed on each of the Claude tests and failed two out of three of the ChatGPT tests.

3. Scribbr

Free – Yes (Unlimited free checks with no sign up)

Paid – No

Pricing – N/A

Test Scores:

AI Generated Text Pass Rate – 4/9 (44%)

Human Written Text Pass Rate – 3/3 (100%)

This tool allows unlimited AI content detection without having to sign up, which is somewhat of a rarity for AI detection tools. It also states on the site that it can detect in multiple other languages - Eng, Fr, Ger, Esp, NL. We only tested in English, so we haven’t verified the accuracy of these other languages.

However, it had mixed results on our tests. It passed tests from Gemini generated writing but fell down on ChatGPT (passed 1/3) and Claude generated writing (passed 0/3).

4. GPTZero

Free – Yes - 10k words per month with basic AI scans and five advanced scans

Paid – Yes

Pricing (Based on lowest per month cost) – $14.99 (150k words per month and basic scans)

Test Scores:

AI Generated Text Pass Rate – 7/9 (78%)

Human Written Text Pass Rate – 3/3 (100%)

Launched in 2023, GPTZero are advocates for responsible AI adoption. It’s easy to use – just paste/write your text, drag and drop files or choose files locally. Once the text is added, it’ll then generate a basic score (or more in-depth feedback for paid users) with a probability of the text being human, mixed, or AI generated.

The tool generally passed the tests though fell under our pass limits on one Gemini and one Claude test text. However, as one of the most known brands in the AI detection field, do test for yourself to decide its validity.

5. ZeroGPT

Free – Yes – 15k characters per AI detection

Paid – Yes

Pricing (Based on lowest per month cost) – $9.99 (100k characters per AI detection and 50 batch files)

Test Scores:

AI Generated Text Pass Rate – 6/9 (67%)

Human Written Text Pass Rate – 1/3 (33%)

This tool provides a fair free limit of 15k characters per AI detection. This scales up if you pay for a license. To use the tool, you copy and paste or upload your text and then it will generate a percentage of how ‘AI generated’ your text is.

Our tests were mixed with this tool. For AI generated writing, it performed well for Gemini text, passing all tests. However, Claude and ChatGPT generated writing were less accurate with three failures out of six tests. It also only detected one of our three human written texts as human-written to our test standard.

6. Writer

Free – Yes

Paid – Yes

Pricing (Based on lowest per month cost) – $39 (likely not needed unless you want the API)

Test Scores:

AI Generated Text Pass Rate – 0/9 (0%)

Human Written Text Pass Rate – 3/3 (100%)

Launched in 2020, Writer is an AI-focused site that targets different industries with its tools. Their detector tool allows you to enter a URL, or you can just add text yourself and check up to 5,000 words. Once your text has been added, it will give you a percentage of how ‘Human generated’ it is.

Unfortunately, this tool did not manage to pass any of our AI generated writing tests using ChatGPT, Gemini and Claude to our pass standard. However, it did pass each of our human written tests. However, as it gave similar output to the AI generated tests, it’s hard to tell the accuracy of this.

7. Copyleaks

Free – Yes (basic results)

Paid - Yes

Pricing (Based on lowest per month cost) – $9.99 (25,000 words per month for two users)

Test Scores:

AI Generated Text Pass Rate – 9/9 (100%)

Human Written Text Pass Rate – 3/3 (100%)

Copyleaks was founded in 2015. The tool is straightforward to use with an App version (if logged in) or a Chrome extension (we did not test the latter).

This tool passed every test we threw at it with AI generated text and human written, which was impressive. They also state that it can detect in over 30 languages too, which is something worth testing if you write in different languages. From our tests, it’s certainly a tool worth testing for yourself.

8. Undetectable AI

Free – Yes

Paid – Yes

Pricing (Based on lowest per month cost) – $19 (20k words per month)

Test Scores:

AI Generated Text Pass Rate – 4/9 (44%)

Human Written Text Pass Rate – 3/3 (100%)

One of a couple in our list of different style AI detector tools as Undetectable AI say that their tool integrates and checks through various AI detection tools – GPTZero, OpenAI, Writer, QuillBot, Copyleaks, Sapling, Grammarly, ZeroGPT – to help give its score even more validity.

You input your text and then see it cycling through the various tools mentioned above to give an ‘AI Detection Likelihood’ percentage.

It had mixed results when tested with AI generated writing. It detected with some accuracy Gemini generated writing but failed all three of our ChatGPT test texts and two out of three Claude texts. It did pass our human-written texts in full, however.

9. Originality.ai

Free – Yes (Though limited before sign-up and subscription)

Paid – Yes

Pricing (Based on lowest per month cost) – $14.95 (200k words per month)

Test Score:

AI Generate Text Pass Rate – 7/9 (77%)

Human Written Text Pass Rate – 3/3 (100%)

Launched in 2022, this site’s principle is that they aren’t against AI generated content but want users to have the information in how to go about using and publishing it.

We tested the free tier, and the tool did pass most of our tests. It did fail on one ChatGPT test text and one Claude test text. It also detected all our human-written tests.

They do give you some free scans before it asks for a subscription, so you should test the output yourself. Though to get more options (e.g. file upload, Chrome extension etc.) you’ll need to sign up.

10. Sapling.ai

Free – Yes

Paid – Yes

Pricing (Based on lowest per month cost) – $25

Test Scores:

AI Generated Text Pass Rate – 6/9 (67%)

Human Written Text Pass Rate – 3/3 (100%)

According to their site, this tool has been developed by former researchers at Berkley, Stanford, Meta and Google. The free version allows you 2000 characters but if you subscribe that is upped to 50k-100k. It can be used for PDFs and DOCX files too.

To use, you simply add your text or upload a file, then click the button to check it. It generates a health bar and percentage score to let you know how AI generated your text is. It also gives you a useful share link if you need one.

The tool detected all the Gemini test texts. It failed to detect one of our ChatGPT texts, but struggled with our Claude generated texts, failing two out of the three tests. It passed our human-written text tests.

11. Turnitin

Free – No

Paid – Yes

Pricing (Based on lowest per month cost) – Unknown (usually targeting academic institutions on more scale than an individual level)

Test Scores:

AI Generated Text Pass Rate – N/A

Human Written Text Pass Rate – NA

Turnitin is specialized in serving the education community since 1998. It’s an established tool within the education sector though some Universities have stopped using it at times. As it usually requires you to be in an academic institution for use, we haven’t been able to test and verify accuracy for ourselves.

12. JustDone

Free – Yes

Paid – Yes

Pricing (Based on lowest per month cost) – $29.99

Test Scores:

AI Generated Text Pass Rate – 8/9 (89%)

Human Written Text Pass Rate – 0/3 (0%)

JustDone’s AI checker allows free tests of text which will give a basic score, but for a more detailed report, you’ll need a paid version. Similar to Undetectable AI, this tool says its scores are ‘double checked’ by other AI detectors – Originality.ai, GPTZero, Copyleaks and Scribbr. The idea is that this will increase the accuracy of the scoring system.

To use it, you can write and paste text or upload a file and then ‘Check for AI Content’ to generate a percentage of how ‘AI’ your text is.

Our test scores showed false positives, as it passed most AI generated text tests (aside from failing one Claude generated text), but identified all human written text as AI generated.

13. SciSpace

Free – Yes (two free tests before signing up)

Paid – Yes

Pricing (Based on lowest per month cost) – $20 (unlimited AI detections)

Test Scores:

AI Generated Text Pass Rate – 0/6 (0%)

Human Written Text Pass Rate – 2/3 (67%)

Starting life as a research formatting tool in 2015, SciSpace has grown into a wider platform with more tools for a writer’s arsenal. It has a ‘Scientific’ and ‘Non-Scientific’ option, which is probably not needed for most, but perhaps is useful to those looking to check scientific formats. It can also check up to 50 pages of PDFs.

This tool has limited free checks before you’re asked to sign up and subscribe. We therefore couldn’t fully test with all test texts; however, based on what we could test, the tool failed all ChatGPT test texts and all Gemini texts. It recognized two out of the three human written texts to our pass standard.

14. Phrasly.ai

Free – Yes (2k word limit for basic reports)

Paid – Yes

Pricing (Based on lowest per month cost) – $19.99

Test Scores:

AI Generated Text Pass Rate – 6/9 (67%)

Human Written Text Pass Rate – 1/3 (33%)

This tool has no restriction on how many times you can use it for free, though it does have a 2k word limit. However, it gives basic output and for text highlighting or more advanced functions, you’d need to subscribe.

The tool is easy to use with a ‘Check for AI’ button, which then generates your score and how many sentences are likely to be AI generated.

In terms of our own tests, there were mixed results with a 67% pass rate for AI generated text. The tool struggled mostly on Claude generated text, failing two out of three of the tests. The test also presented false positives on the human written text, passing one of the three tests.

15. Winston AI

Free – Yes (1,800-character limit)

Paid – Yes

Pricing (Based on lowest per month cost) – $18 (80k credits per month)

Test Scores:

AI Generated Text Pass Rate – 3/3 (100% ChatGPT text)

Human Written Text Pass Rate – N/A

A simple-to-use detector tool where you can upload a file, import from a URL or simply copy and paste text in. You get one free check before being asked to sign up. There is a 14 trial with 2000 credits to test the tool with.

Unfortunately for our purposes, 2000 credits didn’t go very far, so we were only able to run tests on three ChatGPT texts, which the tool passed. However, we’d like to run all tests before making a full assessment of the accuracy of the tool.

16. ContentDetector.ai

Free – Yes (unlimited free checks and word count)

Paid – No

Pricing (Based on lowest per month cost) – N/A

Test Scores:

AI Generated Text Pass Rate – 2/7 (22%)

Human Written Text Pass Rate – 0/3 (0%)

This easy-to-use tool is completely free and unlimited in its use, which is a very good offering, especially as there is no check limit or word count (we tested with large word counts and didn’t hit a limit, though it was slower, of course, to process).

Unfortunately, when we tested it, it didn’t pass many of them for both AI generated and human written text. Out of the three LLMs we generated writing from, it worked better with Gemini (passing 2/3), but it failed on all our ChatGPT and Claude generated texts. However, as it’s free and limitless, it’s worth testing for yourself to judge the accuracy.

17. Grammarly

Free – Yes (10k character limit)

Paid – Yes

Pricing (Based on lowest per month cost) – $30

Test Scores:

AI Generated Text Pass Rate – 0/9 (0%)

Human Written Text Pass Rate – 3/3 (100%)

A well-known brand for writers across the globe, Grammarly have dipped their toes into the AI detector field. You get some free checks before being asked to pay for a pro license.

The tool didn’t pass any of our tests for detecting AI generated content accurately. It did, however, perform better on detecting human-written content.

18. SurgeGraph

Free – Yes

Paid – No

Pricing (Based on lowest per month cost) – N/A

Test Scores:

AI Generated Text Pass Rate – 0/9 (0%)

Human Written Text Pass Rate – 3/3 (100%)

A free to use tool by SurgeGraph who started life focused on SEO before zeroing in on content creation. The tool itself is super simple; you enter your text and then get given a percentage that your text is human written, and a percentage that it’s AI generated. There is also a ‘Sentence Analysis Results’ section, which is where you see which parts of your text are highlighted as AI. A lot of tools only include this with the paid version, so it’s a nice addition.

The tool didn’t pass any of our AI generated writing tests with ChatGPT, Gemini or Claude, but it did detect all human written text well.

19. BrandWell

Free – Yes (2,500 character limit)

Paid – Unsure

Pricing (Based on lowest per month cost) – N/A

Test Scores:

AI Generated Text Pass Rate – 0/9 (0%)

Human Written Text Pass Rate – 3/3 (100%)

BrandWell is a content marketing platform, but it also has a free to use AI Detection tool, so we wanted to give it a test. There are different ways to enter text – copy and paste, write it, upload it from a file or copy from a URL. There is a 2,500-character limit, meaning you may need to break up your text if it’s long. However, once ready, you can click the ‘Detect AI Content’ button and it’ll give you a result if it’s being seen as AI or human content.

The tool did not pass any of the AI generated writing tests, though as it only gives a ‘Passes as Human’ assessment rather than a percentage score, so it’s not the fairest of tests compared to the others on this list who define a score – this certainly is a case of users testing for themselves.

20. Isgen.ai

Free – Yes (5k character limit)

Paid – Yes

Pricing (Based on lowest per month cost) – $5 (150k words per month)

Test Scores:

AI Generated Text Pass Rate – 1/9 (11%)

Human Written Text Pass Rate – 3/3 (100%)

This is a free tool from a site called Isgen.ai. One interesting thing about this tool is the number of languages they say they support – we counted well over 60. We have only been able to test in English but that’s great if they are able to accurately support all those languages.

The free version allows you to either upload a file or paste/write text up to 5k characters. There are paid versions from $5 a month upwards with a scaling amount of word count and other features.

It tested poorly with our AI generated writing, only detecting one out of nine as AI within our test parameters. It did detect all human written content accurately though.

21. AIDP

Free – Yes (three scans per month with sign-up)

Paid – Yes

Pricing (Based on lowest per month cost) – $13.99 (103 scans per month)

Test Scores:

AI Generated Text Pass Rate – 2/3 (67%)

Human Written Text Pass Rate – N/A

We couldn’t test this tool enough to validate it as it only allows three free scans per month (it passed two out of three ChatGPT texts). They state this is because ‘They need to be run on GPUs optimized for AI applications, which are extremely expensive still.’.

To access it, you need to sign up, but once you’re in it’s as straightforward as the other tools on this list. You add your text, and then it’ll generate a score out of 100 for how AI written it believes the text is. It’ll also highlight what it believes are the AI phrases.

22. PerfectEssayWriter

Free – Limited (very limited number of scans)

Paid – Yes

Pricing (Based on lowest per month cost) – $9.99 – 50k words a month and no ads

Test Scores:

AI Generated Text Pass Rate – 0/2 (0%)

Human Written Text Pass Rate – N/A

This AI detector allows you to copy and paste text in, copy from a URL or upload a file. Paid plans start from $9.99 a month to scale the number of words you can scan.

Due to the limit of free scans, we were unable to test the accuracy of this tool in full (it failed on the two ChatGPT texts we tested). However, as with other tools on this list, you paste or upload your content and then it gives you a percentage of how human written or AI generated it believes the text is. It then highlights areas of the text it thinks is likely to be generated with AI.

23. Decopy AI

Free – Yes (No sign-up and can be used 500 times a day with a 200k character limit)

Paid – N/A

Pricing (Based on lowest per month cost) – N/A

Test Scores:

AI Generated Text Pass Rate – 0/9 (0%)

Human Written Text Pass Rate – 0/3 (0%)

This free tool has no sign-up and can be used 500 times a day with a massive 200k character limit. As well as the general scoring of whether your text is AI or human written, you can also generate a PDF or online report to share on the findings.Sadly though, when we tested it with AI and human written text it failed on every test for both AI generated text and human written text. However, due to the fact it is so accessible, you should certainly test this tool for yourself to see how accurate it is for you.

24. Smodin

Free – Yes (5k character limit with 5 free uses per week)

Paid – Yes

Pricing (Based on lowest per month cost) – $15 (unlimited usage with 15k character limit)

Test Scores:

AI Generated Text Pass Rate – 1/9 (11%)

Human Written Text Pass Rate – 3/3 (100%)

This tool allows five free scans per week and gives you a handy ‘Refresh Timer’ so you know how long until it resets – great if you only want a free version. You can upload from a .doc, .docx or PDF file or write/paste text in up to 5k words. This all increases with a paid subscription.

The tool did not do well on our tests with AI generated text, detecting only one Gemini text above 75% as AI content. However, it did recognize all human-written text we tested.

25. NoteGPT

Free – Yes

Paid – No

Pricing (Based on lowest per month cost) – N/A

Test Scores:

AI Generated Text Pass Rate – 6/9 (67%)

Human Written Text Pass Rate – 1/3 (33%)

This tool is a free-to-use ai detector with no sign-up required and no check limit. You paste/write your text or upload a file, click a button and it gives you a percentage score for how much it believes your content is AI generated or human generated. You can then export the results to a PDF or an image, which is handy.

It had mixed results on the tests we ran for AI generated text. It struggled the most with Claude generated writing, failing on two of the three tests. Detecting human written content was an issue too, only passing one of the three of the tests. However, it did detect some per AI/Human, so it is worth verifying with your own tests.

26. Merlin

Free – Yes (3 free checks with 100k limit)

Paid – Yes

Pricing (Based on lowest per month cost) – $19

Test Scores:

AI Generated Text Pass Rate – 6/9 (67%)

Human Written Text Pass Rate – 1/3 (33%)

Merlin allows you three free credits to test with and a large character limit of 100k. There is a paid tier which increases this as well as uses. It’s similar to other tools in our list as you put in your text or upload it, and it’ll generate a percentage score of whether the content is AI or human generated.

It had mixed results when testing, with Claude generated text proving the most difficult for it to accurately access. It only detected one out of our three human written texts too, struggling on the historical documents we tested, but passing with our own written text.

27. Plagium

Free – Yes (5k character check limit)

Paid – Yes

Pricing (Based on lowest per month cost) – $9.99 (143k characters to use per month)

Test Scores:

AI Generated Text Pass Rate – 2/9 (22%)

Human Written Text Pass Rate – 3/3 (100%)

Plagium is a simple-to-use AI detector tool. As with other tools on this list you have the option to write out your text, copy and paste it or upload it to be checked. The tool then spits out a score for you in a form of a health bar – red being AI generated, green being human written.

It didn’t hold up too well on our AI generated text tests, only passing 22%. It passed two out of the three ChatGPT test texts, but it failed to accurately recognize any of the Gemini or Claude generated texts we input. It did better with human written text and recognized them all within our set pass rate.

28. Surfer

Free – Yes

Paid – No

Pricing (Based on lowest per month cost) – N/A

Test Scores:

AI Generated Text Pass Rate – 4/9 (44%)

Human Written Text Pass Rate – 3/3 (100%)

A free tool as part of Surfer’s wider tool set. It’s simple to use – enter or paste your text, click a button, and you get an AI detection score.

Our tests had mixed results with a 44% pass rate on AI generated text. It failed all of our ChatGPT generated writing tests, passed all of the Gemini tests and passed one out of three for Claude generated text. It did, however, detect all human written content, passing all three test texts.

29. Detecting-AI.com

Free – Yes (100 checks per day and 5k character limit)

Paid – Yes

Pricing (Based on lowest per month cost) – $14 (unlimited checks per day with 160k character limit)

Test Scores:

AI Generated Text Pass Rate – 7/9 (78%)

Human Written Text Pass Rate – 2/3 (67%)

This tool is much the same as others with the ability to add written, pasted or upload text to be checked. You get 100 checks per day free with a 5k character limit, which is more than fair. Once you’ve entered your text, the score is shown with highlighted suspected AI text. There are also different models you can test, though we stuck with V2.

Our test yielded mixed results though certainly not the worst performing AI detector. For AI generated text it only failed twice – once with ChatGPT generated text and once with Claude. It failed one out of the three human-written texts. With the number of free uses, it’s certainly worth trying.

30. Crossplag

Free – Yes (Though you must sign up first)

Paid – No

Pricing (Based on lowest per month cost) – N/A

Test Scores:

AI Generated Text Pass Rate – 5/9 (56%)

Human Written Text Pass Rate – 0/3 (0%)

A free AI Detector tool that you can use, though you must sign up first before you can access it. Once you paste in or write your text, you get a kind of heat bar styled score in the ‘AI Content Index’. This will indicate whether your text is human written or AI.

In terms of our tests, the tool had a 56% pass rate for AI generated content with it failing to detect AI generated writing from ChatGPT, Gemini and Claude at times. It also failed to accurately detect our human written text in all three tests.

Which is the best AI Detector?

In terms of our tests we conducted, only two tools passed every test for both AI generated writing and human writing – Pangram Labs (our tool) and CopyLeaks.

However, our view is that whilst we believe we have the most accurate offering, you should test each tool for yourself to see what works best for you.

Our AI Detector Test Methodology

We wanted to run a fair test of each tool, including our own, using the same conditions.

How we conducted our test:

We used the same prompt to generate around 1000 words of:

3 x ChatGPT written text – Model: ChatGPT-4o

3 x Gemini written text – Model: Gemini 2.0

3 x Claude written text – Model: 3.7 Sonnet

We also gathered three human written texts.

1 x Extract from the Declaration of Independence

1 x Extract from the Magna Carta

1 x Our own written text

To pass:

AI generated text – the tool must indicate the writing was at least 75% AI generated (despite it being 100% AI writing originally).

Human written text – the tool must not indicate that the text is more than 25% AI generated.

Caveats:

We ran the test through each tool’s free version. This test is not definitive of the validity of these tools, and they should each be tried and tested by yourself.

We have included our tool in this list. We ran the same test with our tool, but if you are concerned about bias, we have been researched and validated through third-party studies.

We are confident that we are the most accurate and the best AI detection tool available.

Tips to Finding the Best AI Detector

1. Test, test, test

Test different AI detector tools to see how accurate you find them. The best way to do this is to take your own samples of text from AI tools such as ChatGPT and text you know is 100% human written (the latter can be your own or say, a historical document).

You can then test what output is given by the tool and how accurate they are to what you know to be true.

2. Don’t pay money until you’ve tested

Most AI detector tools allow you some kind of free check or trial, perhaps requiring you to sign-up to access. Make use of these initially as you decide if the tool works for you before purchasing a license. Paid versions offer far more value and flexibility, but you don’t want to sign up to a tool only to be disappointed.

3. AI Humanizers

As a leading AI detection tool ourselves, we believe these tools should be made to spot AI writing, but often tools are promoting AI humanizing of text off the back of AI detection. We feel any site doing this presents a red flag as it goes against what we see as the purpose of AI detection, especially for areas such as education – are these tools really trying to help catch AI writing or just bypass systems looking to detect it?

That is something the user will have to decide for themselves as they test AI detectors.

4. Give feedback

Giving feedback to a tool helps the teams behind them understand what is working for you and what isn’t. It also helps you understand who is behind a tool. Is it a focused business with a team who cares or is it a poorly created tool spun up quickly to target keywords?

Talking to a team will help you find out.

If you have any feedback for us, please do get in touch.

Test Our AI Detector for Yourself

We would love for you to test our tool, and you can do so by accessing our Dashboard. However, we also have a Chrome extension and an API to offer you flexibility in how you want to use it.

Sign Up Today