OpenAI upgrading ChatGPT and Codex with two more GPT-6 models

Earlier this month, OpenAI released the first GPT-6 model with Astra. Now GPT-6 is expanding with new GPT-6 Sol and GPT-6 Luna models.

GPT-6 Sol and GPT-6 Luna are now available

Per the ChatGPT desktop app release notes, GPT-6 Sol and GPT-6 Luna will use fewer tokens to run than GPT-5.6 versions of the same class model.

GPT-6 Sol and GPT-6 Luna are rolling out to Codex and ChatGPT Work at lower token prices than their GPT-5.6 predecessors. Use Sol for complex coding and agentic workflows, and Luna for focused, high-volume tasks.

Both models are rolling out to Plus, Pro, Business, Enterprise, and Edu users. Free and Go users can access Luna in the desktop app. Availability depends on rollout and workspace settings; Enterprise administrators must enable the new models. In ChatGPT, the models are available in Work and Codex, but not Chat.

Note the absence of a GPT-6 Terra model. It’s expected that OpenAI is dropping the medium model in favor of just three: Terra (small), Sol (large), and Astra (extra large).

Here’s the official announcement from OpenAI:

While the most demanding and important projects still call for Astra’s full depth, work happens at different scales, rhythms, and budgets.

That’s why we’re expanding the GPT‑6 universe with GPT‑6 Sol and GPT‑6 Luna. GPT‑6 Astra introduced a new generation of intelligence—these models help distribute the benefits of that intelligence by advancing the frontier on cost efficiency. We trained GPT‑6 Sol and Luna with similar methods as GPT‑6 Astra, bringing the advances behind Astra’s state-of-the-art performance in professional work, factuality, coding, computer use, and alignment to faster, more affordable models.