When was o3 released?

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.

How much does o3 cost?

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.

What benchmark scores did o3 get?

o3 reports 1 tracked benchmark score — BullshitBench v2: 26%. Tracked scores may come from lab reports or independent benchmarks; source details accompany the benchmark data.

What is the context window of o3?

o3 has a context window of 200k. That is the maximum amount of input plus output the model can hold in a single request.

No. o3 is a closed model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.

What came before and after o3?

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.

o3

Released Apr 16 2025

o3 is an AI model released by OpenAI on Wednesday, Apr 16 2025, 2 days after GPT-4.1 nano. It has a 200k token context window. Benchmark results (shown below) cover BullshitBench v2.

API pricing

Input: $2.00
Cached input: $0.50
Output: $8.00

Reasoning or thinking is supported.

USD per 1M tokens

Available from


OpenAI	$2.00	$8.00	200K

USD per 1M tokens

Benchmarks

BullshitBench v2

26%

#64 of 97

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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.

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%. Tracked scores may come from lab reports or independent benchmarks; source details accompany the benchmark data.
: o3 has a context window of 200k. That is the maximum amount of input plus output the model can hold in a single request.
: No. o3 is a closed 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.