GPT-5.6 API pricing

The gpt-5-6 family is a three-step price ladder rather than three different capabilities. Luna, terra and sol declare identical context windows of 1,050,000 tokens and identical parameter support, reasoning, tools, structured output and vision, and differ only by a constant factor: $1, $2.50 and $5 per million input tokens, $6, $15 and $30 output. Each step up multiplies the bill by 2.5 then 2, so the top of the ladder costs five times the bottom for the same request shape. Cached input stays at ten percent of input throughout, and the surcharge above 272K input tokens applies to all three.

The rest of the range, and every rate OpenAI publishes: OpenAI API pricing