GPT-5.6 is OpenAI's model family released for general availability on July 9, 2026. It includes three tiers: Sol for frontier capability, Terra for a balance of intelligence and cost, and Luna for fast, cost-sensitive, high-volume workloads.

When was GPT-5.6 released?

OpenAI announced a limited preview on June 26, 2026, and released GPT-5.6 for general availability on July 9, 2026. It is available across ChatGPT, Codex, and the OpenAI API.

How much does GPT-5.6 cost?

Standard API pricing is $5 input and $30 output per million tokens for Sol, $2.50 input and $15 output for Terra, and $1 input and $6 output for Luna. Prompts above 272,000 input tokens are charged at twice the input rate and 1.5 times the output rate for the full request.

What is the GPT-5.6 context window?

All three GPT-5.6 API models support a 1,050,000-token context window and a 128,000-token maximum output. Their knowledge cutoff is February 16, 2026. Context limits in ChatGPT can be lower and vary by plan and surface.

Is GPT-5.6 available in ChatGPT?

Yes. Plus, Pro, Business, and Enterprise users access GPT-5.6 Sol through medium and higher reasoning-effort settings. Pro and Enterprise users can also select Sol Pro. In ChatGPT Work and Codex, Free and Go users access Terra, while Plus, Pro, Business, and Enterprise users can choose among all three tiers.

Is there a GPT-5.6 Pro or Mini?

There is no model named GPT-5.6 Mini. OpenAI's API documentation describes Terra as roughly corresponding to the mini tier in earlier GPT-5 families and Luna as roughly corresponding to the nano tier. Pro is not a separate GPT-5.6 API model. It is an execution mode that works with any GPT-5.6 API model through reasoning.mode: "pro". In ChatGPT, OpenAI surfaces GPT-5.6 Sol Pro for eligible Pro and Enterprise users.