o1
Summary
o1 is a proprietary language model from OpenAI, released on 5 Dec 2024. 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 $15 per million input tokens and $60 per million output tokens (OpenRouter), across 1 provider we track. OpenAI has deprecated this model.
O-series reasoning model for hard analysis, math, coding, and planning
Last verified 4 Oct 2026. Every figure on this page links to its source.
Specifications
| Developer | OpenAI |
|---|---|
| Release date | 5 Dec 2024 [models.dev] |
| Status | Deprecated [models.dev] |
| Weights | Proprietary (API only) [models.dev] |
| Context window | 200K (200,000 tokens) [models.dev] |
| Max output | 100K tokens [models.dev] |
| Knowledge cutoff | Sept 2023 [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] |
o1 API pricing by provider
USD per million tokens. Sorted by input price.
| Provider | Input | Output | Cached input | Context | Source |
|---|---|---|---|---|---|
| OpenRouter openai/o1 | $15 | $60 | $7.50 | 200K | OpenRouter, 4 Oct 2026 |
Frequently asked questions
What is the context window of o1?
o1 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 o1 API cost?
o1 is listed from $15 per million input tokens and $60 per million output tokens (OpenRouter). Prices last verified 4 Oct 2026.
Is o1 open source?
No. o1 is a proprietary model; OpenAI has not released its weights. It is available through APIs including OpenRouter.
When was o1 released?
OpenAI released o1 on 5 Dec 2024, according to models.dev.
Change history
No changes detected since we started tracking this model. We re-check every source daily.