o3

About

o3 is OpenAI's specialized reasoning model designed for deep, step-by-step logical inference — fundamentally different from standard language models that generate answers directly. Instead of producing an answer in a single forward pass, o3 works through problems systematically, generating and evaluating multiple reasoning chains before arriving at its final answer. This approach, often called chain-of-thought reasoning, makes o3 exceptionally effective for mathematical proofs, complex logic puzzles, scientific reasoning, multi-step analysis, competitive programming, and any task requiring careful, verifiable reasoning. On benchmarks like AIME 2025 (87.3%), GPQA Diamond (81.2%), and FrontierMath, o3 sets new standards, significantly outperforming standard models that rely on pattern matching rather than deliberate reasoning. The trade-off is speed: o3 takes longer to generate answers because it's effectively running multiple reasoning processes internally. This makes it unsuitable for real-time chat, creative writing, or simple Q&A where immediate responses are expected. o3 is a text-only model without multimodal capabilities, and its per-token cost is higher than standard models due to the internal reasoning computation. Available through ChatGPT Plus (USD 20 per month) with limited reasoning messages, and Pro (USD 200 per month) for unlimited deep reasoning. For mathematicians working on proofs, scientists analyzing complex data, programmers solving algorithmic challenges, and anyone who needs verifiable step-by-step reasoning, o3 represents a new category of AI capability — not just faster at existing tasks, but capable of types of reasoning that standard models cannot reliably perform. Compared to DeepSeek-R1, o3 generally achieves higher scores on reasoning benchmarks but is not available as open-weight.

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