o3-mini
OpenAI's compact reasoning model optimized for fast, cost-efficient problem-solving with exceptional performance in math, coding, and science.
OpenAI Compact reasoning model for math and code
o3-mini is a text generation model developed by OpenAI and released in January 2025. It belongs to OpenAI's o-series, a family of models trained to reason through problems step by step before producing a response. The model is designed to balance reasoning quality with speed and cost efficiency, making it practical for high-volume deployments where deliberate thinking is needed without long wait times.
o3-mini is particularly well-suited for tasks involving mathematical reasoning, programming challenges, and scientific questions. It operates with a 200,000-token context window, allowing it to process long documents, extended codebases, or multi-turn conversations in a single session. The model generates output at approximately 137 tokens per second and uses an internal reasoning process rather than responding immediately, which contributes to its accuracy on structured, logic-intensive tasks.
What o3-mini supports
Mathematical Reasoning
Applies step-by-step internal reasoning to solve math problems, from algebra to competition-level challenges. Performs well on formal mathematical benchmarks.
Code Generation
Generates, debugs, and explains code across common programming languages. Well-suited for technical problem-solving tasks that require logical precision.
Scientific Reasoning
Handles graduate-level scientific questions, including those tested by benchmarks like GPQA Diamond covering biology, chemistry, and physics.
Large Context Window
Supports a 200,000-token context window, equivalent to roughly 300 pages of text, enabling processing of long documents or extended conversations.
Fast Inference
Produces output at approximately 137 tokens per second, enabling responsive interactions even on queries that require internal reasoning steps.
Chain-of-Thought Reasoning
Uses an internal reasoning process before generating a final answer, improving accuracy on structured and multi-step problems.
Ready to build with o3-mini?
Get Started FreeBenchmark scores
Scores represent accuracy — the percentage of questions answered correctly on each test.
| Benchmark | What it tests | Score |
|---|---|---|
| MMLU-Pro | Expert knowledge across 14 academic disciplines | 79.1% |
| GPQA Diamond | PhD-level science questions (biology, physics, chemistry) | 74.8% |
| MATH-500 | Undergraduate and competition-level math problems | 97.3% |
| AIME 2024 | American math olympiad problems | 77.0% |
| LiveCodeBench | Real-world coding tasks from recent competitions | 71.7% |
| HLE | Questions that challenge frontier models across many domains | 8.7% |
| SciCode | Scientific research coding and numerical methods | 39.9% |
Common questions about o3-mini
What is the context window size for o3-mini?
o3-mini supports a 200,000-token context window, which is roughly equivalent to 300 pages of text. This allows it to handle long documents, large codebases, and extended multi-turn conversations in a single session.
When was o3-mini released and what is its training data cutoff?
o3-mini was released in January 2025. The training date listed in the metadata is January 2025. For specific knowledge cutoff details, refer to OpenAI's official model release notes.
What types of tasks is o3-mini best suited for?
o3-mini is designed for tasks that benefit from deliberate, step-by-step reasoning, including mathematical problem-solving, code generation and debugging, and scientific reasoning. It is particularly effective where logical accuracy matters more than conversational fluency.
How does o3-mini's reasoning process work?
o3-mini is a proprietary reasoning model that thinks through problems internally before producing a final response. This internal reasoning step is not visible to the user but contributes to improved accuracy on structured and logic-intensive tasks.
Is o3-mini still available, or has it been replaced?
o3-mini has been succeeded by o4-mini but remains available as a capable option for users who need reliable reasoning at scale. It can be accessed through MindStudio without requiring separate API key management.
What people think about o3-mini
The Reddit threads found do not directly discuss o3-mini in depth. One thread references o3-mini-medium as a benchmark comparison point when evaluating a third-party model, suggesting the community uses it as a known reference for reasoning performance.
The threads are primarily focused on other models rather than o3-mini itself, so direct community sentiment about o3-mini's strengths or limitations cannot be reliably summarized from this data.
Qwen 3 !!!
XBai o4 is live and claiming to beat OpenAI's o3-mini-medium in reasoning with parallel thinking, fast inference, and better web search.
Documentation & links
Parameters & options
Used to give the model guidance on how many reasoning tokens it should generate before creating a response to the prompt. Low will favor speed and economical token usage, and high will favor more complete reasoning at the cost of more tokens generated and slower responses. The default value is medium, which is a balance between speed and reasoning accuracy.
Explore similar models
OpenAI GPT‑5.2 Pro
The most capable model series yet for professional knowledge work.
OpenAI GPT-5.1
The best model for coding and agentic tasks across domains
OpenAI GPT-5
The best model for coding and agentic tasks across domains
Google Gemini 3.1 Pro
Google's frontier reasoning model delivering enhanced software engineering, agentic reliability, and multimodal intelligence across a 1M-token context window.
Nvidia Nemotron 3 Nano 30B
NVIDIA's compact open-weight hybrid MoE model with 30B total / 3.5B active parameters, delivering strong reasoning and coding performance up to 1M context.
X.ai Grok 4.20 Reasoning
A beta reasoning variant of xAI's Grok 4.20, designed for enhanced step-by-step thinking and complex problem-solving.
Start building with o3-mini
No API keys required. Create AI-powered workflows with o3-mini in minutes — free.