OpenAI: GPT-6 Astra (Fast)
GPT-6 Astra (Fast) is a reasoning model from OpenAI released on Sep 4, 2026. It reads text, images and files and writes text, with a 1.05M token context window and up to 128K tokens per reply.
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It costs $20 per million input tokens and $100 per million output tokens. Cached input bills at $2, 90% less than fresh input.
It supports tool calling, structured JSON output and prompt caching.
- Modalities
- In / out price
- $20 / $100 per 1M
- Context
- 1.05M
- Max output
- 128K
- Released
- Sep 4, 2026
- Knowledge cutoff
- n/a
- Tool calling
- Structured output
- Reasoning
- Prompt caching
- Open weights
- Free to use
GPT-6 Astra (Fast) pricing
USD, as listed on Oct 15, 2026. Most bills are input heavy, so the cached input rate matters as much as the headline price.
| Input | $20 / 1M tokens | |
|---|---|---|
| Output | $100 / 1M tokens | |
| Cached input (read) | $2 / 1M tokens | 90% off input |
| Cache write | $25 / 1M tokens | |
| Prompts over 200K | $40 in, $150 out | long context rate |
| Prompts over 272K | $40 in, $150 out | long context rate |
What GPT-6 Astra (Fast) costs per month
Pick a workload close to yours or type your own volumes.
Supported request parameters
What you can set when you call GPT-6 Astra (Fast) through an OpenAI compatible API.
- Tools
tools - Structured outputs
structured_outputs - Reasoning
reasoning
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GPT-6 Astra (Fast) questions
How much does the GPT-6 Astra (Fast) API cost?
$20 per million input tokens and $100 per million output tokens, with cached input at $2. Prompts over 200K tokens bill at $40 input and $150 output. The estimator on this page turns that into a monthly bill for your own workload.
What is the context window of GPT-6 Astra (Fast)?
1,050,000 tokens of input, and it can write up to 128,000 tokens in one reply. As a rough guide, a million tokens is around 750,000 English words.
Does GPT-6 Astra (Fast) support tool calling?
Yes. It accepts tool definitions and can return JSON that matches a schema, which is what an agent needs to call your APIs.
Is GPT-6 Astra (Fast) open source?
No. OpenAI serves it through an API only, so you cannot download the weights or host it yourself.
When was GPT-6 Astra (Fast) released?
Sep 4, 2026.
Catalog data from models.dev (MIT licensed), refreshed daily, last on Oct 15, 2026. The summary is written from these facts.
Building on GPT-6 Astra (Fast)?
I test your real tasks on it and the two closest alternatives, then ship the agent on whichever wins on cost and accuracy.
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