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OpenAI · Model

GPT-6 Astra pricing, context window and specs

GPT-6 Astra costs $10 per million input tokens and $50 per million output tokens, and reads up to 1,050,000 tokens per request. By blended price it is number 9 of OpenAI’s 10 current models here, counting from the cheapest.

Input / 1M
$10
Output / 1M
$50
Cached / 1M
$1
Context
1,050,000
Max output
128,000
Released
2026-09-04

Estimate your cost with GPT-6 AstraCompare all OpenAI modelsCount tokens for GPT-6 Astra

Pricing

GPT-6 Astra API pricing

Price per 1M tokensInputOutput
Standard$10$50
Cached input (read)$1–
Cache write$12.50–
Batch API$5$25
Prompts of 272,000+ tokens$20$75

Output costs 5.0× the input price, so long replies drive the bill more than long prompts. If your requests share a long fixed prefix, such as a system prompt or tool definitions, caching cuts that part to 10% of the normal input price. Once a single prompt reaches 272,000 tokens, the whole request is billed at the higher long-context rate shown above.

Examples

What GPT-6 Astra costs in practice

WorkloadTokens in / outRequests/dayPer requestPer month
Support chatbot50% cached1,500 / 4001,000$0.0283$859.27
RAG app20% cached6,000 / 500500$0.0742$1,128
Coding agent80% cached40,000 / 2,000200$0.21$1,290
Document summariserbatch8,000 / 600300$0.055$501.88

Change any number in the cost calculator.

Context

Context window

GPT-6 Astra accepts up to 1,050,000 tokens per request, roughly 787,500 English words or 1,575 pages. That budget is shared between your prompt and the reply, and a single reply is capped at 128,000 tokens.

Filling the whole window with one prompt costs about $21.00 at list price, so for repeated long-document work, retrieval (sending only the relevant parts) or prompt caching is usually much cheaper.

Check whether your text fits GPT-6 Astra’s window.

Features

Capabilities

Image input
Yes
Tool / function calling
Yes
Reasoning mode
Yes
Prompt caching
Yes
Structured output
Yes
Open weights
No
Accepts
file, image, text
Knowledge cutoff
Not published

As declared by the provider’s API. It shows a feature exists, not how well it works.

API

GPT-6 Astra model ID

OpenRouter
openai/gpt-6-astra
OpenAI API
gpt-6-astra (pinned)

OpenAI lists GPT-6 Astra as current. Every GPT model ID, with aliases and snapshots.

OpenAI

Where GPT-6 Astra sits in OpenAI’s line-up

Ranked by blended price (three parts input to one part output, $20 per 1M for GPT-6 Astra), it is number 9 of OpenAI’s 10 current models here, counting from the cheapest. One step down, GPT-5.5 costs $11.25 blended (44% less). It has the same published limits and features as GPT-6 Astra. One step up, GPT-5.5 Pro costs $67.50 (3.4× as much). It has the same published limits and features as GPT-6 Astra. See every OpenAI model and price

ModelInput / 1MOutput / 1MContextReleased
gpt-oss-120b$0.037$0.17131,0722025-08-05
GPT-6 Luna$0.10$0.501,050,0002026-09-22
GPT-4o-mini$0.15$0.60128,0002024-07-18
GPT-5.4 Mini$0.75$4.50400,0002026-03-17
GPT-6.1 Sol$2$101,050,0002026-09-29
GPT-4o$2.50$10128,0002024-05-13
GPT-5.6 Terra$2$121,050,0002026-07-09
GPT-5.5$5$301,050,0002026-04-24
GPT-6 Astra (this page)$10$501,050,0002026-09-04
GPT-5.5 Pro$30$1801,050,0002026-04-24

OpenAI’s current models with a page here, cheapest first. Older and superseded models are listed on the provider page and in the comparison table.

Save

Cheaper alternatives

Current models from major providers, one per provider, that keep image input, tool calling, a reasoning mode, a usable context window and output limit. Compared by blended price.

Compare

Similarly priced models

Current models from other major providers, closest blended price.

FAQ

GPT-6 Astra questions

How much does GPT-6 Astra cost?

GPT-6 Astra costs $10 per million input tokens and $50 per million output tokens, with cached input at $1. A typical chatbot reply (1,500 tokens in, 400 out) costs about $0.035. Use the LLM cost calculator for your own workload.

What is GPT-6 Astra’s context window?

1,050,000 tokens, about 787,500 English words or 1,575 printed pages, shared between your prompt and the reply. A single reply can be up to 128,000 tokens.

Does GPT-6 Astra support prompt caching and batch requests?

Yes, cached input is billed at $1 per million tokens (10% of the normal input price), and writing a prompt to the cache costs $12.50 per million tokens. A batch API is available at $5 input and $25 output per million tokens.

What are cheaper alternatives to GPT-6 Astra?

With the same essentials (image input and tool calling), the cheapest options are Qwen3.8 Max (0902) (85% cheaper), GPT-6.1 Sol (80% cheaper), Claude Sonnet 5.5 (80% cheaper). Cheaper doesn’t mean equivalent, so test them on your own prompts.

What is the API model ID for GPT-6 Astra?

On OpenRouter it is openai/gpt-6-astra. In OpenAI’s own API, use gpt-6-astra; OpenAI lists the model as current. The GPT model ID list has every alias and snapshot. Pass the ID as the model value in each request.

Is GPT-6 Astra open source?

No, GPT-6 Astra is only available through OpenAI’s API and partners; its weights aren’t published.

Updated

Sources: OpenRouter models API and LiteLLM model prices and context windows, checked daily; open-weight prices are typical hosted prices. Confirm critical numbers on OpenAI’s pricing page. See our methodology.