Introducing GPT-6 Sol and Luna

What changed

Source summary

OpenAI released two new GPT-6 models, Sol and Luna, priced 50% lower than their GPT-5.6 predecessors. Sol targets complex tasks like coding, while Luna is built for high-volume, well-defined work such as summarising and extracting information; both are now available in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise and Edu users, with Luna also free on desktop.

Why it matters to your work

Practical interpretation

If your team uses ChatGPT for routine work like summarising documents or drafting quick answers, the new Luna model handles that kind of high-volume task more cheaply, while Sol is a stronger option for anything code-heavy. Both are already live for eligible paid ChatGPT plans, so it's worth trying them for tasks you'd normally hand to a slower or pricier model.

When this could help

Worth evaluating when you are currently paying for Astra and want to test whether Sol handles your workload at lower cost, or when you need a capable but cheap model for high-volume tasks where Luna's quality is sufficient.

GPT-6 Sol delivers close to Astra quality on coding, document analysis, computer use, and research at roughly a fifth of Astra's price. Luna is the cheapest GPT-6 tier, matching or exceeding GPT-5.6 Sol on many benchmarks at a hundredth of the cost. Both cut API pricing 50% from GPT-5.6 promotional rates.

How to get started

1. In ChatGPT Work or Codex, select GPT-6 Sol or Luna from the model picker.

   Provider guidance ↗

2. For API usage, set the model parameter to gpt-6-sol or gpt-6-luna. Adjust reasoning effort and tool availability without breaking the prompt cache.

   Provider guidance ↗

Build it into your routine

SCALA suggested workflow

1. Cost-conscious model tiering

   Default to Luna for routine tasks and high-volume API calls. Escalate to Sol for complex professional work (coding, document review, research). Reserve Astra for the hardest tasks where Sol falls short. Review your usage weekly to see if you can shift more workload down the tier ladder.

What to check

• Not available in the standard ChatGPT Chat tab at launch — only in Work and Codex. Source ↗
• Free and Go users can only access Luna, and only in the desktop app. Source ↗
• Benchmark results come from OpenAI's research environment or API, which may differ from production ChatGPT. Some comparisons omit competitor fallback costs. Source ↗