OpenAI released the O3 Mini in early 2025. This smaller reasoning model is built for STEM tasks and offers better intelligence and lower latency than the O1 Mini. Users can choose low, medium, or high reasoning effort. It can also be used to create high-value, cost-effective, real-time use.
STEM Raising Performance
O3 Mini performs very well at a medium effort level. It equals the larger O1 model’s functions but responds faster and more accurately.
- In the 2024 AIME Math Test, O3 Mini with high reasoning effort did better than both O1 Mini and the full O1 model.
- Reputation coding (Codeforces): O3 Mini achieves an ELO rating of 27/27, significantly higher than O1 Mini’s 1891. It outperforms the O1 Mini high in programming tasks.
- On the GPQA Diamond Science Test, O3 Mini scored 87.7% on PhD-level questions, which is 10% better than O1 Mini.
- In software engineering tests (SWE Bench Verified), O3 Mini is the top performer in its series. With significant effort, it solves complex tasks and often beats the O1 Mini by more than 20% in software benchmarks.
- Experts found that O3 Mini made 39% fewer major errors than O1 Mini.
Latency and Speed Metrics
- Training effort customization: users can select low, medium, or high effort to trade off speed and accuracy. Models are 63% cheaper than the O1 Mini.
- Advanced features:
- Supports function calling
- Structured outputs and developer messages
- One limitation is that O3 Mini does not support vision features like the O1 model.
Comparison with other models.
- Compared to the O1 Mini, the O3 Mini is faster, cheaper, and more accurate. It also does better in coding and math competitions.
- Versus DeepSeek R1: While DeepSeek R1 is frequently more cost-effective per token, O3 Mini is generally faster for live coding and STEM tasks, and it shows superior safety with a lower rate of unsafe responses (1.19% versus 11.98%).
Today we’re launching OpenAI O3 Mini, our latest and most affordable reasoning model, now available in ChatGPT and through the API. First reviewed in December 2024, this fast and capable model pushes the limits of small models, offering strong STEM skills, especially in science, math, and coding. It also keeps the low cost and fast response times of OpenAI O1 Mini.
OpenAI O3 Mini is our first small reasoning model to support popular developer features like function calling, structured outputs, and developer messages, making it ready for production use right away. Like OpenAI O1 Mini and O1 Preview, O3 Mini also supports streaming. Developers can choose from three reasoning effort options: low, medium, or high, to fit their needs best. This means O3 Mini can focus more on tough problems or work faster when speed matters. O3 Mini does not handle vision tasks, so developers should use OpenAI for those starting today. O3 Mini is available in the Chat Completions API, Assistance API, and Batch API for select developers in API user tiers 3-5.
Starting today, ChatGPT Plus, Team, and Pro users can use OpenAI O3 Mini, and Enterprise users will get access in February. O3 Mini will replace O1 Mini in the model picker, offering higher rate limits and faster responses. This makes it a great choice for coding, STEM, and logic tasks. Plus and Team users will now have their daily message limit increased from 50 to 150 with O3 Mini. O3 Mini also now supports search, helping users find current answers with links to web sources. The search feature is an early prototype while we work to add it to more models.
Free plan users can now try O3 OpenAI O3 Mini by choosing a region in the message composer or by regenerating a response. This is the first time a reasoning model has been available to two free ChatGPT users.
OpenAI O1 remains our main model for general knowledge, while OpenAI O3 Mini is designed for technical fields that require accuracy and speed. In ChatGPT, O3 Mini uses a medium level of understanding effort to balance speed and accuracy. Paid users can also choose O3 Mini High in the model picker for a smarter version that takes a bit longer to reply. Pro users get unlimited access to both O3 Mini and O3 Mini High.
Fast, Powerful, And Built For STEM Reasoning
Tech: OpenAI O1 and O3 Mini are tuned for STEM reasoning. With medium reasoning effort, O3 Mini matches O1’s performance in math, coding, and science, but responds faster. Expert testers found that O3 Mini provides more accurate, clearer answers with better reasoning than O1 Mini. They preferred O3 Mini’s answers 56% of the time and saw 39% fewer major errors on tough real-world questions. With moderate effort, O3 Mini matches O1’s results on challenging tasks, such as AIME and GPQA.
What’s Next?
The launch of OpenAI O3 Mini is another step forward in our effort to make cost-effective intelligence possible. We have improved the rationale for STEM fields and kept costs low so people can access high-quality AI. Since GPT-4, we have reduced per-token pricing by 95% while still offering strong reasoning abilities. As more people use AI, we are committed to leading the way by building models that are smart, efficient, and safe at scale.
Source: OpenAI o3‑mini
