OpenAI Launches GPT-6 Sol and Luna, Cutting API Prices 50% Versus GPT-5.6

OpenAI released GPT-6 Sol and GPT-6 Luna on September 22, 2026, pitching both on lower cost and fewer mistakes.

The Prices

At standard API rates, GPT-6 Sol costs $2 per million input tokens and $10 per million output tokens. GPT-6 Luna costs $0.10 per million input tokens and $0.50 per million output tokens.

Half the Cost of GPT-5.6

The new models arrived with permanent pricing that cuts API costs by 50% versus the GPT-5.6 series. Both accept text and images as input and return text.

A 20x Spread Inside One Family

The gap between Sol and Luna is twentyfold on both input and output. For production systems, that spread is the real story: routing simple classification, extraction and summarization to the cheaper model while reserving the larger one for harder reasoning can change the economics of an AI feature more than any single price cut.

What Teams Should Do Now

If you priced an AI feature on GPT-5.6 rates, it is worth re-running the numbers — and re-testing quality, since a cheaper tier may now be good enough for tasks that previously needed the top model.