GPT-4.1 vs GPT-4o: The AI Accuracy Battle, Which Model Hallucinates Less?

OpenAI is once again in the spotlight after the launch of GPT-4.1, which is claimed to have a much lower hallucination rate than GPT-4o. The debate over accuracy, efficiency, and default model selection in the ChatGPT app is heating up, especially among professional users demanding minimal hallucination. So, how do GPT-4.1 and GPT-4o actually compare in terms of numbers, performance, and the business logic behind OpenAI’s choice of default model?

Hallucination Rate: Who Leads the Pack?

GPT-4.1 stands out with a hallucination rate of around 2%, significantly lower than GPT-4o’s 37.1–61.8% (data: HuggingFace Hallucination Leaderboard). This reduction directly impacts the factual reliability of AI responses, especially for research, medical, and legal needs where accuracy is critical.

It’s Not Just About Accuracy: Why Is GPT-4o Still Default?

Although GPT-4.1 is more accurate, OpenAI has chosen GPT-4o as the default in ChatGPT due to speed, efficiency, and user experience factors. GPT-4o was designed as a multimodal model—it handles text, voice, and images in real time with low latency, making it perfect for daily chats, voice conversations, and seamless image uploads.

Same Limits, More Efficient Operational Costs

Many users ask, if GPT-4.1 now shares the same usage limits as GPT-4o and is even cheaper to run than the classic GPT-4, why not make GPT-4.1 the default? The answer lies in server optimization, multi-modal feature consistency, and the need for a standard user experience for hundreds of millions of daily users. OpenAI emphasizes that GPT-4o can serve more users simultaneously without sacrificing speed.

Product Strategy and Feature Standardization

From a business perspective, GPT-4o is prioritized for all of ChatGPT’s flagship features. Live voice conversation, real-time image analysis, and integrated API only run reliably on GPT-4o. Meanwhile, GPT-4.1 is positioned as a premium model for specialized needs—such as legal drafting, scientific research, or any application where hallucination must be nearly zero.

When Should You Choose GPT-4.1?

If you require maximum accuracy and minimal risk of misinformation, GPT-4.1 remains available for manual selection by Plus or Enterprise users. However, for daily use, GPT-4o is more than capable and efficient as the main “engine” powering ChatGPT.

Choose Based on Your Needs

The GPT-4.1 vs GPT-4o showdown isn’t just about accuracy. Speed, cost-efficiency, feature integration, and user experience are key factors behind the default model decision. For more about OpenAI’s technology, visit the OpenAI Blog.