How do AI detectors work: Methodology
It is important to understand the essence—to look "under the hood" of the benchmarks—to be sure the text is being checked exactly the way it needs to be. There are masses of different content verification methods; sometimes company marketers simply shout loudly about one of them without explaining much. As a result, we see figures like "99% accuracy," but we don't know what accuracy they are talking about. When using such an AI detection tool, we experience disappointment and waste our time.
To truly understand how to detect AI generated text, one dataset might not show the full picture, so we are relying on research that utilized over 15 datasets.
We will highlight the main ones here. If you are interested in reviewing the full report yourself, follow the link.
Why the MGTD benchmark matters
MGTD isn't just another single-dataset test. The platform aggregates 15+ benchmarks: MGTBench, RAID, SemEval 2024, M4, MultiSocial, SAID, and others. Nearly 2 million text samples total. Domains range from scientific abstracts and student essays to Twitter posts and Reddit threads. Languages include English, Chinese, Russian, Arabic, Urdu, and over twenty more. Generators cover GPT-2/3/4, LLaMA, Mistral, Claude, ChatGPT, Cohere, and beyond.
What does this mean in practice? A detector scoring 99% on one dataset can collapse on another. MGTD eliminates such flukes: consistent performance across 15 different benchmarks is no longer luck — it's reliability. The platform also features an open leaderboard where any developer can submit predictions and receive objective scores, with no way to game the test.
Most accurate AI detector: 2026 Ratings
In this comparison, we looked at how AI detectors behave across different data types and metrics. The goal is to clearly show which AI checker in 2026 actually delivers a stable result, and which ones only win in isolated scenarios.
| Detector |
ROC-AUC |
MIDAS |
MIDAS-SEG |
| It's AI Top |
0.920 |
0.949 |
0.9558 |
| GPTZero |
0.887 |
0.746 |
0.7926 |
| Originality AI |
0.825 |
0.630 |
0.7288 |
| Binoculars |
0.775 |
0.397 |
— |
| ZeroGPT |
0.714 |
0.603 |
0.6330 |
The table shows individual metrics; below we have compiled the results into a general AI text detector rating, taking into account stability of performance, absence of critical errors, and overall predictability of detection.
It's AI
Average ROC-AUC: 0.920
The first thing that catches the eye is stability. Other AI detectors show excellent results in one specific place but give a weaker performance in others. It's AI holds the standard everywhere.
Segmentation at the 0.9558 level means the ability to see not just "the text is suspicious," but specifically "these three paragraphs were written by AI."
|
Pros:
- ✔Works consistently on new models (LLaMA3, Mistral, Qwen)
- ✔Best segmentation among all tested
- ✔API for integration
- ✔Best on short texts
- ✔Quick checks via Chrome extension
|
Cons:
|
It seems the training was conducted on a wide spectrum of models, not just the GPT family. When students switch from ChatGPT to Claude or the new Qwen, many detectors get lost. It's AI keeps working.
GPTZero
Average ROC-AUC: 0.887
Many users ask, is GPTZero accurate? On RAID (the dataset with evasion attacks), the GPTZero AI detector scores 0.985—a practically ideal result. While it took a slight hit on newer tests, we have to pay our respects to the veteran. Did a student run the text through a paraphraser? It will catch them. Did they replace letters with similar Unicode characters? It will catch them. This is its territory.
|
Pros:
- ✔Integration with Canvas and Microsoft Word
|
Cons:
- ✘Struggles with segmentation models (MIDAS-SEG 0.7926)
- ✘Weak on instruction-tuned models
- ✘Accuracy drops to 0.75 on short texts
|
If your students use ChatGPT and try to cheat the system—GPTZero will handle it. If someone smart switches to Mistral or Qwen—the result becomes less accurate.
Originality AI
Average ROC-AUC: 0.825
The "AI + Plagiarism" combo in one tool is convenient for publishers. But it's worth thinking about what is more important: the comfort of using a single tool or a higher probability of accurate verification.
|
Pros:
- ✔Combined AI + plagiarism check
- ✔Chrome extension for quick checks
- ✔API for integration
|
Cons:
- ✘Overall accuracy is 10% lower than the leaders
- ✘Strange unevenness across languages
- ✘Weak segmentation
|
For a publisher that needs both checks and for whom maximum AI detection accuracy isn't critical—a reasonable choice. If accuracy is more important than convenience—there are better options.
Binoculars
Average ROC-AUC: 0.775
Binoculars uses a metric method—it calculates statistical properties of the text (perplexity, cross-entropy), rather than training a neural network. This works when AI models generate with obvious statistical patterns. But modern models, especially instruction-tuned ones, have learned to write close to human level.
Open-source—the only one in the top list with open code. You can look at every line, understand the logic, and tweak it for yourself. For researchers, this is valuable.
|
Pros:
- ✔Open-source, full transparency
|
Cons:
- ✘A disaster on modern models
- ✘No segmentation
|
For working with classic datasets or rare languages—a good choice. For detecting texts from new models—it won't fit.
ZeroGPT
Average ROC-AUC: 0.714
The only fully free AI checker on the list. No limits, no subscriptions. But the numbers explain why this is possible. So, is ZeroGPT accurate?
Independent testers ran classic literature through ZeroGPT—the King James Bible, Shakespeare. The detector flagged them as "likely AI" with high percentages. This is a sign of bad training—the model catches false patterns. The formal language of the classics is statistically similar to some AI generations.
|
Pros:
|
Cons:
- ✘Low accuracy on all datasets
- ✘Worst on instruction-tuned models (0.527)
- ✘Flags classic literature as AI
- ✘No visible updates
|
For a quick check out of curiosity—it can be used. For decisions with consequences (academia, HR, publishing)—no.
Free AI detector: The difference in accuracy
All tested detectors have free options—a trial for a couple of thousand words or a limited plan. ZeroGPT is an AI detector free of charge and shows a ROC-AUC of 0.714. It's AI is paid and shows 0.920.
A difference of 20 percentage points is roughly every fifth AI text missed. Is this critical for your task? If you are checking a diploma—yes. If it's an article from the internet just for curiosity—probably not.
However, the results of the independent MGTD benchmark show an important trend regarding the tools tested above: free services often lag in accuracy when working with new neural network models. Where other tools show unstable results, It's AI demonstrates the smoothest and highest indicators in all testing scenarios.
Try it yourself and verify the quality of the check on your own texts.
