o1
Released
o1 is an AI model released by OpenAI on Thursday, Dec 5 2024, 84 days after o1-mini. It has a 200k token context window. Benchmark results (shown below) cover GPQA Diamond.
API pricing
- InputWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it.
- $15.00
- 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.
- $7.50
- OutputWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one.
- $60.00
Benchmarks
About
o1, released December 5, 2024 after a September preview, was the first production reasoning model: instead of answering immediately, it generates a long private chain of thought trained with reinforcement learning before responding. The approach produced dramatic gains on competition mathematics, science, and hard coding problems that had resisted ordinary scaling.
o1 established the test-time-compute paradigm that reshaped the entire industry — within months every major lab shipped a reasoning model, from DeepSeek R1 to Gemini 2.5 Pro to Claude 3.7 Sonnet's extended thinking. Its own line moved fast too: o3-mini arrived in January 2025 and the full o3 in April 2025.
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Frequently asked questions
o1 was released by OpenAI on Thursday, Dec 5 2024.
o1 was built by OpenAI. Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.
o1 costs $15.00 per million input tokens and $60.00 per million output tokens through the OpenAI API. Cached input is $7.50 per million tokens. Rates are pay-as-you-go API prices verified against OpenAI's published pricing on August 18, 2026.
o1 reports 1 tracked benchmark score — GPQA Diamond: 75.7%. Scores are the figures published at release by OpenAI.
o1 has a context window of 200k. That is the maximum amount of input plus output the model can hold in a single request.
No. o1 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 o1-mini on Sep 12 2024, 84 days earlier. It was followed by o3-mini on Jan 31 2025.