# o1

o1 is an AI model released by OpenAI on Dec 5 2024. It has a 200k context window. Tracked results include 75.7% on GPQA Diamond.

## Facts

| Field | Value |
| --- | --- |
| Model | o1 |
| Developer | OpenAI |
| Release date | Thursday, Dec 5 2024 |
| Licensing | Closed |
| Context window | 200k |

## API pricing

All rates in USD per 1,000,000 tokens, pay-as-you-go.

| Tier | Input | Cached input | Output |
| --- | --- | --- | --- |
| All documented contexts | $15.00 | $7.50 | $60.00 |

Verified October 19, 2026 against the first-party source: https://developers.openai.com/api/docs/models/o1

## Tracked benchmark scores

| Benchmark | Score | Source | What it measures |
| --- | --- | --- | --- |
| GPQA Diamond | 75.7% | Lab | Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. |

## About o1

OpenAI introduced the full o1 model in ChatGPT on December 5, 2024, following September's o1-preview. The release continued the reasoning-model approach of spending additional computation before producing an answer. OpenAI positioned it for difficult mathematics, science and programming tasks and introduced a separate pro mode that used more computation for demanding requests.

The December 5 announcement was tied to ChatGPT Pro and paid ChatGPT access. Developer API availability followed separately, so the date should not be read as a simultaneous release in every interface. OpenAI evaluated pro mode using a stricter four-out-of-four reliability measure in addition to ordinary benchmark accuracy, distinguishing consistency across attempts from success on a single answer.

## Questions and answers

### When was o1 released?

o1 was released by OpenAI on Thursday, Dec 5 2024.

### Who made o1?

o1 was built by OpenAI. Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.

### How much does o1 cost?

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 October 19, 2026.

### What benchmark scores did o1 get?

o1 reports 1 tracked benchmark score — GPQA Diamond: 75.7%. Tracked scores may come from lab reports or independent benchmarks; source details accompany the benchmark data.

### What is the context window of o1?

o1 has a context window of 200k. Providers may specify separate input and output token limits.

### Is o1 open source?

No. o1 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 o1?

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.


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Canonical page: https://aireleasetracker.com/model/openai/o1
Site index: https://aireleasetracker.com/llms.txt
Source: AI Release Tracker (https://aireleasetracker.com). Most benchmark scores come from lab launch material; gathered results identify the leaderboard that published them.