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10 GPTZero Alternatives in 2024

GPTZero is a reliable AI detector, but it’s far from the only one. Here are ten alternatives worth considering.
Updated May 14, 2024
“No AI allowed”, generated with Midjourney
“No AI allowed”, generated with Midjourney

In the face of uncertainty, GPTZero stands as one of the few AI detection tools that can actually prevent AI misuse at a reliable rate. But sometimes, we just want something new. After all, there’s always something better on the horizon.

So, for AI detectors, what are some alternatives that can actually measure up or even surpass GPTZero? In this article, we’ll introduce you to ten of them, and tell you which ones are actually worth investing in. Are you ready?


Topping our list today is perhaps the most reliable AI detection tool in the market today. Copyleaks is an AI and plagiarism analysis tool that’s getting more popular by the minute. With advanced processing, it can determine in a matter of seconds if a text or even code came from an existing source or AI.

So, how good is it really? An independent study says that it’s more than 99% accurate in detecting AI-generated content. In our own testing, we found it to be 75% accurate in true positive cases and 80% in false positive cases. This is good enough to be included in our three most recommended AI detectors, showcasing precision even with human-written content.

Copyleaks has a free version, but you can avail of their full version starting from $9.99 for 100 pages monthly to $455.99 for 10,000 pages.

Sapling AI

Sapling is an AI-powered writing assistant and content detector platform. Their most popular feature is AI detection, which is built by engineers from Google, Meta, Stanford, and UC Berkeley — so, it has to be good, right?

Good news: it absolutely is. During our 2024 test, Sapling AI came second in true positive cases with 87.04% and first in false positive cases with 93.84%, beating even premium AI detectors. What’s more is that it’s completely free, and unlike other free AI detectors, it comes with an AI likelihood score.

Originality AI

As far as AI detection goes, Originality AI is one of the earliest in the market and is still one of the best for good reason. This AI and plagiarism checker remains a solid choice for anyone who’s looking to prevent content dishonesty, with a weighted score of 70.29% for true and false positive tests in our 2024 article.

Originality AI has a credit-based pricing which is offered two ways: first as a monthly subscription of 2000 credits for $14.95 or as a pay-as-you-go service starting from $30 for 3000 credits. Each credit will scan 100 words.

Winston AI

Another popular option is Winston AI, which is a standalone AI detection platform made to tackle every LLM there is. Despite a 59.2% average false positive score in our test, it still secured the top spot for true positive AI content with a strong 91.92% — but that doesn’t tell the whole story. In fact, Winston AI went 11/12 (all correct scores being 100%) in our test that included text tweaked by Undetectable AI, an AI bypasser.

But this accuracy literally comes with a price. They have a free trial of 2000 words, but after that, their cheapest version (when paid annually) comes at $12 per month for 80,000 words and their most premium option is priced at $19 per month for 200,000 words.


CrossPlag is the first AI detector that I’ll feature here that wasn’t included in our 2024 AI detection accuracy testing, but it definitely deserves a mention. It’s one of the few AI detectors that supports multilingual input. An article by Undetectable AI also classifies it as one of the most accurate AI detectors in the market.

CrossPlag’s AI detector is completely free to use but it does require you to sign up for an account.


Did you know that QuillBot also has an AI detector built into their platform? This writing assistant’s diverse features keep growing by the minute. Although we don’t have an accurate reading yet of how well it prevents AI misuse, a quick test using text directly from ChatGPT shows that this platform shows promise in AI detection.

Unlike their other features, QuillBot’s AI detector is completely free, but it does have a 1200-word limitation every run.


Like QuillBot, Scribbr (another popular writing assistant) also offers a built-in AI detection software. Using the same text I used to test QuillBot, it appears that — to no-one’s surprise — Scribbr’s AI detection algorithm is accurate and has a quick turnaround time.

Scribbr’s AI detector is free for 500 words, but you have to subscribe to their premium plagiarism checker to get its full prowess. This starts at $19.95 and can scale up to $39.95 for bulk processing.


If you’re worried about false positives more than anything, then ZeroGPT is also a good option for your AI detection needs. This platform didn’t do too well in our 2024 testing in true positives, but it’s still in our top 5 for false positives, earning it a mention for GPTZero alternatives.

It already has a robust free version, which accepts up to 15,000 characters per run, but you can also get their premium version for $9.99/month or $26.99/month for enterprise needs.

Content at Scale

Content at Scale has always been one of our favorite products here in Gold Penguin. Apart from having one of the best AI writing assistants for blogs, it also has a strong AI detection feature that was in our top 5 for 2024 accuracy testing with a weighted true and false positive score of 67.64%.

For 2500 characters per run, you can use Content at Scale’s AI detector for free without an AI likelihood score. If you need more than that, you need to subscribe to their premium tier (inclusive of their Generative AI suite) which is $49/month.


SciSpace is a recent discovery of mine, and I’m liking what I see so far. Unlike other AI detectors, this one focuses only on preventing AI misuse in academic spaces — saving teachers and students from having to deal with false positives.

You can use SciSpace for free, but it does have one drawback. You can only use it for 1000 words per run.

The Bottom Line

GPTZero is one of the best AI detectors in the market, so picking an alternative might be quite tricky. However, if I were to choose the best out of everything I’ve mentioned, I already have three in mind:

Copyleaks, Sapling, and Winston AI.

The reason boils down to two: accuracy and experience. These three have proven time and again that they’re extremely accurate despite AI detection being faulty most times. I’ve also used them the most out of all AI detectors, so I can personally attest to their effectiveness in stopping AI misuse while preventing false positives.

Did we miss anything? Feel free to comment down below. In the meantime, can I interest you in similar articles such as this one or this one? Have fun!

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Written by John Angelo Yap
Hi, I'm Angelo. I'm currently an undergraduate student studying Software Engineering. Now, you might be wondering, what is a computer science student doing writing for Gold Penguin? I took up studying computer science because it was practical and because I was good at it. But, if I had the chance, I'd be writing for a career. Building worlds and adjectivizing nouns for no other reason other than they sound good. And that's why I'm here.
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