OpenAI announces o3 and o4-mini reasoning models for ChatGPT

During an OpenAI livestream, the ChatGPT maker demoed its o-series models, o3 and o4-mini. Here are the details about what it can do and who has access.

Apr 16, 2025 - 18:38

OpenAI announces o3 and o4-mini reasoning models for ChatGPT

OpenAI's o3 and o4-mini models for ChatGPT have arrived.

As expected, the ChatGPT maker released the newest versions of its reasoning models. OpenAI launched o1, its first reasoning or chain-of-thought model, last summer and skipped over o2 to announce its progress on o3 in late December. While o3 has not been publicly available yet until today, OpenAI now has a lightweight version, o3-mini on the market.

In the livestream, the OpenAI team (sans CEO Sam Altman) described some of the models' capabilities and demoed how users can use o3 and o4-mini. The models have been trained to use tools and can process prompts that include uploaded images.

Initially, in an effort to streamline its numerous and somewhat confusing model options, Altman said they wouldn't release o3 and o4-mini as standalone models, and would instead integrate their capabilities into GPT-5. But a few weeks later, the company pivoted and decided to release the two models after all and delay the GPT-5 launch. Again.

Skeptics say the multiple delays of GPT-5 indicate internal struggles to significantly improve model performance. But Altman says the wait will be worth it. In the meantime, o3 and o4-mini have been deemed strong enough models to exist on their own.

o3 and o4-mini are available today on ChatGPT and the API.

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