# GPT-6 release date: when GPT-6 Astra, Sol and Luna came out By SeedRouter · Published 2026-09-29 · Updated 2026-09-29 GPT-6 is out. OpenAI released GPT-6 Astra on September 3, 2026, first to a limited set of organizations and then more widely over the following days. GPT-6 Sol and GPT-6 Luna followed on September 22, 2026, completing the GPT-6 family of three models. All three are available in the OpenAI API today; in ChatGPT, which ones you get depends on your plan. Every date below comes from OpenAI's announcements, API changelog and help center, checked on September 29, 2026. ## When was GPT-6 released? | Model | Released | First available in | | ----------- | ------------------ | --------------------------------------------------------------------------------------------- | | GPT-6 Astra | September 3, 2026 | A limited set of organizations, then ChatGPT, the OpenAI API, Microsoft Azure and AWS Bedrock | | GPT-6 Sol | September 22, 2026 | ChatGPT Work and Codex, and the OpenAI API | | GPT-6 Luna | September 22, 2026 | ChatGPT Work and Codex, and the OpenAI API | OpenAI's API changelog records both dates: on September 3, "Released GPT-6 Astra, our most capable model, built for the hardest end-to-end work", and on September 22, "Released GPT-6 Sol (`gpt-6-sol`) and GPT-6 Luna (`gpt-6-luna`)." ## How did GPT-6 Astra roll out? In stages. OpenAI's announcement said: "GPT‑6 Astra is rolling out today to a limited set of organizations and over the coming days will become available to all ChatGPT Plus, Pro, Business, and Enterprise users, as well as through the OpenAI API, Microsoft Azure, and AWS Bedrock." ChatGPT's release notes for September 3 were more cautious: "Access is rolling out to a limited set of organizations. Astra is not yet generally available. Broader availability is planned over the coming days." If you could not find Astra in the first days after launch, that is why. For Enterprise workspaces, OpenAI added that "access is off by default at launch": an admin has to turn it on. ## When did GPT-6 Sol and GPT-6 Luna come out? On September 22, 2026. OpenAI's announcement: > "GPT‑6 Sol and GPT‑6 Luna are available in ChatGPT Work and Codex starting today for all Plus, Pro, Business, Enterprise, and Edu users. Free and Go users can access GPT‑6 Luna in the desktop app. These models are not yet available in Chat. In the OpenAI API, they are available as gpt-6-sol and gpt-6-luna." OpenAI also said it would roll the two models out in ChatGPT "gradually throughout the day", so some users saw them later on September 22 than others. ## What is GPT-6 Astra, and how is it different from Sol and Luna? GPT-6 is a family of three models, each with its own model ID. OpenAI describes them this way: * **GPT-6 Astra** (`gpt-6-astra`): "Our most capable model, built for the hardest end-to-end work". * **GPT-6 Sol** (`gpt-6-sol`): "Built to power complex coding and agentic workflows." * **GPT-6 Luna** (`gpt-6-luna`): "Our most efficient model for focused, high-volume tasks." Which one to use, and how they score on OpenAI's benchmarks, is covered in [GPT-6 Astra vs Sol vs Luna](https://seedrouter.ai/blog/gpt-6-astra-vs-sol-vs-luna). ## What is GPT-6 Pro? A ChatGPT option powered by GPT-6 Astra. OpenAI's help center says: "GPT-6 Pro, powered by GPT-6 Astra, is available in ChatGPT for" the Pro, Business and Enterprise plans, with usage limits that depend on the plan. [Is GPT-6 free?](https://seedrouter.ai/blog/is-gpt-6-free) lists what each ChatGPT plan includes. ## What are GPT-6's specs? All three models share a 1,050,000-token context window with up to 922,000 input tokens, write up to 128,000 tokens per request, and take text and images as input with text as output. They differ in reasoning effort levels and knowledge cutoff: April 30, 2026 for Astra, April 20 for Sol and May 18 for Luna. The full side-by-side table is in [GPT-6 Astra vs Sol vs Luna](https://seedrouter.ai/blog/gpt-6-astra-vs-sol-vs-luna), reasoning effort settings are in the [GPT-6 API guide](https://seedrouter.ai/blog/gpt-6-api), and what changed from the previous generation is in [GPT-6 vs GPT-5.6](https://seedrouter.ai/blog/gpt-6-vs-gpt-5-6). ## Where can I use GPT-6 today? * **In ChatGPT**, depending on your plan. See [Is GPT-6 free?](https://seedrouter.ai/blog/is-gpt-6-free). * **In Codex**, with a ChatGPT sign-in or an API key. See [GPT-6 in Codex](https://seedrouter.ai/blog/gpt-6-codex). * **Through an API.** OpenAI's API serves all three models. GPT-6 Astra was also announced for Microsoft Azure and AWS Bedrock. * **On SeedRouter**, you can call `gpt-6-astra`, `gpt-6-sol` and `gpt-6-luna` with one key through the OpenAI SDK, using Chat Completions or the Responses API. You top up once with no subscription, credits never expire, and a failed request is not charged. Live rates are on each model page and in the [GPT-6 pricing guide](https://seedrouter.ai/blog/gpt-6-api-pricing). ## Frequently asked questions ### Is GPT-6 out yet? Yes. GPT-6 Astra was released on September 3, 2026, and GPT-6 Sol and GPT-6 Luna on September 22, 2026. ### When did GPT-6 Astra come out? On September 3, 2026, first for a limited set of organizations, with wider availability over the following days. ### Is GPT-6 the same as GPT-6 Astra? GPT-6 is the family name. GPT-6 Astra is its most capable model; GPT-6 Sol and GPT-6 Luna are the other two. ### Is GPT-6 available in ChatGPT's Chat? GPT-6 Pro, powered by GPT-6 Astra, is available in ChatGPT on the Pro, Business and Enterprise plans. At launch, OpenAI said GPT-6 Sol and GPT-6 Luna were "not yet available in Chat" and were offered in ChatGPT Work and Codex instead. ### What is GPT-6's knowledge cutoff? April 30, 2026 for GPT-6 Astra, April 20, 2026 for GPT-6 Sol and May 18, 2026 for GPT-6 Luna. ## Call GPT-6 now Try [GPT-6 Astra](https://seedrouter.ai/models/gpt-6-astra), [GPT-6 Sol](https://seedrouter.ai/models/gpt-6-sol) or [GPT-6 Luna](https://seedrouter.ai/models/gpt-6-luna) with one SeedRouter key. The [GPT-6 Astra API reference](https://seedrouter.ai/docs/gpt-6-astra) lists every parameter, and the [GPT-6 API guide](https://seedrouter.ai/blog/gpt-6-api) walks through the first request.