IndexGPT-6 and GPT-5.6
GPT-6 and GPT-5.6
A search for GPT-6 lands on OpenAI’s GPT-5.6 announcement. The shipped family is GPT-5.6, with Luna, Terra, and Sol. OpenAI has not published a model whose name is GPT-6.
Updated 2026-09-27
The page that ranks for the query is GPT-5.6. Treat “GPT-6” as the name people guess for the next flagship, not as a model id you can pass to the API.
What GPT-5.6 is
GPT-5.6 is the current named family after GPT-5.4 left ChatGPT. OpenAI’s developer update cut API prices on that family: Luna down 80 percent, Terra down 20 percent, plus a faster Sol option. Those percentages are the announcement, not a quote you should hard-code. The rate card on the API pricing page is the number you pay.
Older ChatGPT labels still get searched. ChatGPT 5.1 and ChatGPT 5.4 are earlier releases. 5.4 stopped being offered to signed-in ChatGPT users on 31 August 2026 and stayed on the API.
Questions
Is GPT-6 out?
Not under that name. The release people are pointing at is GPT-5.6.
Which GPT-5.6 model should I call?
Luna, Terra, and Sol are the three names in the price cut. Pick from the live model list in the API or the ChatGPT model menu, not from a blog nickname.
Related notes
- ChatGPT 5.4
ChatGPT 5.4 and 5.4 mini left the signed-in ChatGPT app on 31 August 2026. Both remain on the API and on Codex sessions that use an API key.
- ChatGPT 5.1
ChatGPT 5.1 is an earlier ChatGPT model release. Newer pickers default to later 5.x models, including GPT-5.6.
- GPT Realtime
GPT Realtime is OpenAI’s low-latency speech model on the API. It is billed as API usage, not as a ChatGPT Plus add-on.
- How much is ChatGPT?
ChatGPT Plus is $20 a month. Pro is listed at $100 and $200, with new $200 sign-ups paused. API usage is a separate bill.