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OpenAI cuts GPT-5.6 Luna price by 80%, Terra by 20%

OpenAI cuts GPT-5.6 Luna price by 80%, Terra by 20%

3 Key Points

  1. What happened

    OpenAI announced price cuts for two GPT-5.6 models: Luna, its fastest and most affordable model, now costs 80% less, and Terra, its balanced model for everyday work, costs 20% less. The lower prices also apply to how usage is counted against paid subscriptions in Codex and ChatGPT Work.

  2. Why it matters

    Luna delivers performance comparable to frontier-class models from a year ago at roughly 6 cents on the dollar per task and nearly nine times the speed. On professional work as measured by Agents' Last Exam, Luna outperforms Fable 5 at an estimated cost per task nearly 99% lower, making high-volume AI workflows practical at scale.

  3. What to watch

    OpenAI also introduced Fast mode in the API, which delivers up to 2.5× faster speeds than Standard processing for GPT-5.6 Sol at twice the price with no change in intelligence. Starting July 30, API pricing is $2 per million input tokens and $12 per million output tokens for Terra, and $0.20 per million input tokens and $1.20 per million output tokens for Luna.

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Context & Analysis

OpenAI's price cuts come a day after the company described how GPT-5.6 helped make itself more efficient to run. The company credits improvements across models, inference systems, and the agentic harness for reducing the time, tokens, and cost required for each result. GPT-5.6 Sol played a key role in this process by autonomously rewriting and optimizing production kernels, which helped reduce the end-to-end cost of serving the model by 20%, and by running experiments that increased token-generation efficiency by more than 15%.

These efficiency gains are now being passed to customers, reflecting OpenAI's stated mission to make advanced intelligence more abundant and affordable. The strategy aims to serve both ends of the price-performance curve: lower-cost models like Luna make high-volume work economical at scale, while Fast mode gives API customers quicker access to Sol when response time is critical. Businesses can now define the outcome and quality standard they need, then choose between models like Sol for complex planning and Luna for well-specified implementation tasks.

The price cuts' real impact likely hinges on whether enterprises actually shift high-volume workloads to Luna and Terra at the new rates. If Luna performs on par with year-old frontier models at such a steep discount, more businesses may find it practical to run AI across broader operations like document analysis and customer-interaction classification. The feedback loop OpenAI describes—where more capable models help improve efficiency further—suggests that today's reductions may not be the last, should the company continue to find compounding gains.

FAQ
When do the new API prices take effect?
Starting July 30, API pricing is $2 per million input tokens and $12 per million output tokens for Terra. Luna is priced at $0.20 per million input tokens and $1.20 per million output tokens.
What is Fast mode for GPT-5.6 Sol?
Fast mode replaces Priority Processing in the API and delivers up to 2.5× faster speeds than Standard processing at twice the price, with no change in intelligence. Existing API requests tagged priority will continue to work.
How much cheaper is Luna compared to a year-old frontier model?
Luna delivers performance comparable to models that were frontier-class a year ago at roughly 6 cents on the dollar per task, and at nearly nine times the speed.

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