Advancing the price-performance frontier with GPT‑5.6

OpenAI is cutting prices for GPT-5.6 Luna by 80% and GPT-5.6 Terra by 20%, effective July 30. Luna now costs $0.20 per million input tokens and $1.20 per million output tokens; Terra costs $2 per million input and $12 per million output. A new Fast mode for GPT-5.6 Sol replaces Priority Processing, delivering up to 2.5× faster speeds at twice the standard price. These changes stem from efficiency improvements across model architecture, inference systems, and agentic tooling — including Sol autonomously optimizing production kernels (reducing serving costs 20%) and improving token-generation efficiency by 15%. The GPT-5.6 family is designed to let enterprises mix models across workflow stages, using Sol for complex reasoning and Luna for high-volume, well-specified tasks at a fraction of the cost.