o3
Summary
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.
Deliberate o-series reasoner for hard math, coding, and multi-step analysis
Last verified 4 Oct 2026. Every figure on this page links to its source.
Specifications
| Developer | OpenAI |
|---|---|
| Release date | 16 Apr 2025 [models.dev] |
| Status | Generally available [models.dev] |
| Weights | Proprietary (API only) [models.dev] |
| Context window | 200K (200,000 tokens) [models.dev] |
| Max output | 100K tokens [models.dev] |
| Knowledge cutoff | May 2024 [models.dev] |
| Input | Text, images and PDFs [models.dev] |
| Output | Text [models.dev] |
| Reasoning mode | Yes [models.dev] |
| Tool calling | Yes [models.dev] |
| Structured output | Yes [models.dev] |
o3 API pricing by provider
USD per million tokens. Sorted by input price.
| Provider | Input | Output | Cached input | Context | Source |
|---|---|---|---|---|---|
| OpenAI API o3 | $2 | $8 | $0.50 | 200K | models.dev, 4 Oct 2026 |
| Azure AI Foundry o3 | $2 | $8 | $0.50 | 200K | models.dev, 4 Oct 2026 |
| OpenRouter openai/o3 | $2 | $8 | $0.50 | 200K | OpenRouter, 4 Oct 2026 |
| Vercel AI Gateway openai/o3 | $2 | $8 | $0.50 | 200K | models.dev, 4 Oct 2026 |
| Vercel AI Gateway openai/o3-fast | $3.50 | $14 | $0.88 | 200K | models.dev, 4 Oct 2026 |
Frequently asked questions
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.
Change history
No changes detected since we started tracking this model. We re-check every source daily.
Sources
- https://github.com/sst/models.dev/blob/dev/providers/openai/models/o3.toml
- https://github.com/sst/models.dev/blob/dev/providers/azure/models/o3.toml
- https://openrouter.ai/openai/o3
- https://github.com/sst/models.dev/blob/dev/providers/vercel/models/openai/o3.toml
- https://github.com/sst/models.dev/blob/dev/providers/vercel/models/openai/o3-fast.toml