GPT-6 Astra

GPT-6 Astra is the model OpenAI labels the highest-intelligence option in its GPT-6 family, aimed at complex reasoning, coding, computer use, research and document work. It launched on September 3, 2026 with a 1.05M-token context window and reasoning effort settings from low to max. OpenAI's safety overview says it is the first model to reach the Critical cybersecurity level in its Preparedness Framework.

By OpenAIReleased September 3, 2026Data checked October 10, 2026

CurrentClosedFrontier

Specifications

Context window: 1.05Mabout 788,000 words, or 1,580 pages
Max output: 125Ktokens per response
Input price: $10per 1M tokens
Output price: $50per 1M tokens
Cached input: $1per 1M tokens
Weights: ClosedProprietary
Parameters: Undisclosed
Input types: Text, Images
Output types: Text
Reasoning mode: Yes
Tool calling: Yes
Released: Sep 3, 2026Current

Standard rates for prompts up to 272K input tokens; a larger prompt costs $20 input, $2 cached and $75 output for the whole request. Batch and Flex 50% off; Fast mode 2x. Regional-processing endpoints add 10%.

What it costs in practice

Workload	Monthly cost at list price
Support chatbot30,000 conversations a month, 2,000 input and 400 output tokens each	$1,200
Document summaries2,000 documents a month, 12,000 input and 800 output tokens each	$320
Coding agent1,000 tasks a month, 60,000 input and 6,000 output tokens each	$900

Standard rates, no caching or batch discounts. Run your own numbers.

Strengths

1.05M-token context window and 128K-token output limit
Reasoning effort from low to max
Responses API tools include web search, code interpreter, computer use and MCP

Trade-offs to weigh

$10 input and $50 output per million tokens, five times GPT-6.1 Sol
No 'none' reasoning setting for low-latency calls

Where it fits

OpenAI positions GPT-6 Astra for:

reasoningcodingagentsresearchlong documents

Where you can use it

API
ChatGPT
OpenRouter

Alternatives to consider

Model	Tier	Context	Input / output per 1M
Claude Fable 5.1Anthropic	Frontier	1M	$10 / $50	Compare
Claude Opus 5.5Anthropic	Frontier	1M	$4 / $20	Compare
Gemini 3.1 ProGoogle	Frontier	1M	$2 / $12	Compare
Kimi K3Moonshot AI	Frontier	1M	$3 / $15	Compare

Frequently asked questions

How much does GPT-6 Astra cost?

GPT-6 Astra lists at $10 per million input tokens and $50 per million output tokens, with cached input at $1 (checked October 10, 2026). Standard rates for prompts up to 272K input tokens; a larger prompt costs $20 input, $2 cached and $75 output for the whole request. Batch and Flex 50% off; Fast mode 2x. Regional-processing endpoints add 10%. Confirm current rates on the provider's pricing page before you commit.

What is the context window of GPT-6 Astra?

GPT-6 Astra accepts up to 1,050,000 tokens of context (about 788,000 words, or 1,580 pages), and it can write up to 125K tokens in a single response. Long prompts cost more and can be slower, so most apps send only what the task needs.

Is GPT-6 Astra open source?

No. GPT-6 Astra is a proprietary model from OpenAI; its weights aren't published. You can use it through the OpenAI API and through ChatGPT, OpenRouter.

What is GPT-6 Astra best for?

OpenAI positions GPT-6 Astra for reasoning, coding, agents, research. It accepts text, images as input, has a reasoning (thinking) mode and supports tool calling. Test it on a sample of your own tasks before you choose it for production.

Sources

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