OpenAI Debuts GPT-6 Sol and GPT-6 Luna at Half the API Price
OpenAI announced GPT-6 Sol and GPT-6 Luna on September 22, 2026. Both models are trained with the same method as the top-tier GPT-6 Astra, and both cost less than half the API price of the GPT-5.6 series. GPT-6 Sol is built for complex work and coding, priced at $2 per million input tokens and $10 per million output tokens. GPT-6 Luna targets low-cost, high-volume use, at $0.10 per million input tokens and $0.50 per million output tokens. According to OpenAI, internal factuality evaluations put GPT-6 Sol at roughly half the error rate of GPT-5.6 Sol. Both models have rolled out to ChatGPT Plus, Pro, Business, Enterprise, and Edu subscribers in ChatGPT Work and Codex, but neither is available yet in regular Chat. Free and Go plan users can use GPT-6 Luna on the desktop version of ChatGPT.