o3
OpenAI · o-series
High-reasoning model optimized for difficult analysis, planning, and reliability-critical decisions.
Overview
Freshness note: Model capabilities, limits, and pricing can change quickly. This profile is a point-in-time snapshot last verified on February 15, 2026.
o3 is positioned for difficult reasoning-heavy tasks where accuracy and deep stepwise analysis matter more than low cost or raw throughput. OpenAI now recommends GPT-5 for most use cases, but still documents o3 as a specialized reasoning option for teams that want the o-series behavior profile.
Capabilities
The model performs strongly on multi-step analysis, constraint-heavy planning, and ambiguity resolution. It is useful for high-stakes reasoning in engineering design, operations strategy, and risk evaluation.
Technical Details
o3 belongs to OpenAI’s reasoning-focused family and is often used as a specialized model rather than a universal default. It works best when prompts specify assumptions, constraints, and desired decision criteria.
Pricing & Access
Available through OpenAI API surfaces where reasoning-focused models are offered. Pricing and limits may change by product and account tier; verify current values before production budgeting.
Best Use Cases
Strong choice for architecture tradeoff analysis, migration planning, incident root-cause reasoning, policy interpretation, and other tasks where robust chain-of-thought-style reasoning is valuable.
Comparisons
Compared with GPT-5, o3 is often chosen for harder reasoning depth rather than broad general utility. Compared with DeepSeek-Reasoner, o3 may provide stronger integrated ecosystem support at potentially higher cost. Compared with Claude Opus 4.6, selection depends on reasoning style preference and platform alignment.