# o3

> o3 is a proprietary language model from OpenAI, released on 16 Apr 2025. It accepts text, images and PDFs and generates text, with a 200K-token context window and up to 100K output tokens per response. As of 4 Oct 2026, the lowest listed API price is $2 per million input tokens and $8 per million output tokens (OpenAI API), across 4 providers we track.

Source page: https://www.aimodel.directory/models/o3
Last verified: 4 Oct 2026

## Specifications

- **Developer:** OpenAI
- **Release date:** 16 Apr 2025 (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Status:** Generally available (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Weights:** Proprietary (API only) (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Context window:** 200K (200,000 tokens) (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Max output:** 100K tokens (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Knowledge cutoff:** May 2024 (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Input:** Text, images and PDFs (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Output:** Text (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Reasoning mode:** Yes (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Tool calling:** Yes (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)
- **Structured output:** Yes (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml)

## API pricing (USD per 1M tokens)

| Provider | Input | Output | Cached input | Context |
|---|---|---|---|---|
| OpenAI API | $2 | $8 | $0.50 | 200K |
| Azure AI Foundry | $2 | $8 | $0.50 | 200K |
| OpenRouter | $2 | $8 | $0.50 | 200K |
| Vercel AI Gateway | $2 | $8 | $0.50 | 200K |
| Vercel AI Gateway | $3.50 | $14 | $0.88 | 200K |

## FAQ

### What is the context window of o3?

o3 has a context window of 200,000 tokens (200K) and can generate up to 100,000 tokens in a single response, according to models.dev.

### How much does the o3 API cost?

Through OpenAI API, o3 costs $2 per million input tokens and $8 per million output tokens. Prices last verified 4 Oct 2026.

### Is o3 open source?

No. o3 is a proprietary model; OpenAI has not released its weights. It is available through APIs including OpenAI API, Azure AI Foundry, OpenRouter, Vercel AI Gateway.

### When was o3 released?

OpenAI released o3 on 16 Apr 2025, according to models.dev.

### Which providers offer o3?

We track o3 on 4 providers: OpenAI API, Azure AI Foundry, OpenRouter, Vercel AI Gateway.

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Data licensed CC BY 4.0. Cite as: AI Model Directory, "o3", https://www.aimodel.directory/models/o3