o3
Released
o3 is an AI model released by OpenAI on Wednesday, Apr 16 2025, 2 days after GPT-4.1 nano. Benchmark results (shown below) cover BullshitBench v2.
API pricing
- InputWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it.
- $2.00
- Cached inputA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again.
- $0.50
- OutputWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one.
- $8.00
Benchmarks
About
o3, released April 16, 2025 alongside o4-mini, was OpenAI's most capable reasoning model of the o-series era and the first to combine extended reasoning with full agentic tool use in ChatGPT — searching the web, running Python, and analysing images inside its chain of thought. First previewed in December 2024 with breakthrough ARC-AGI results, it took four months to reach general availability.
In practice o3 became the model of choice for hard analytical work — mathematics, research questions, multi-step debugging — while GPT-4.1 handled everyday tasks. o3-pro followed in June 2025 for even longer reasoning budgets. The separate o-series branding ended when GPT-5 unified fast and reasoning models under one system in August 2025.
Compare o3 with
Suggested comparisons
Frequently asked questions
o3 was released by OpenAI on Wednesday, Apr 16 2025.
o3 was built by OpenAI. Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.
o3 costs $2.00 per million input tokens and $8.00 per million output tokens through the OpenAI API. Cached input is $0.50 per million tokens. Rates are pay-as-you-go API prices verified against OpenAI's published pricing on August 18, 2026.
o3 reports 1 tracked benchmark score — BullshitBench v2: 26%. Scores are the figures published at release by OpenAI.
No. o3 is a proprietary model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.
OpenAI's previous tracked release was GPT-4.1 nano on Apr 14 2025, 2 days earlier. It was followed by o4-mini on Apr 16 2025.