OpenAI Cuts GPT-5.6 Terra and Luna Prices
OpenAI cut API prices for GPT-5.6 Terra by 20% and GPT-5.6 Luna by 80% on July 30, while also reducing how their use counts against ChatGPT Work and Codex subscription limits. OpenAI lists the new API prices at $2 per million input tokens and $12 per million output tokens for Terra, and $0.20 and $1.20, respectively, for Luna. The company also replaced Priority Processing with Fast mode for GPT-5.6 Sol.
OpenAI cut prices for two GPT-5.6 API models on July 30, lowering GPT-5.6 Terra by 20% and GPT-5.6 Luna by 80%. The company also changed how Terra and Luna usage counts against paid ChatGPT Work and Codex subscriptions, allowing subscribers to run more tasks before reaching their usage limits.
9to5Mac reported that Terra now costs $2 per million input tokens and $12 per million output tokens, while Luna costs $0.20 per million input tokens and $1.20 per million output tokens. The outlet also noted that monthly ChatGPT Work and Codex subscription prices remain unchanged.
API processing update
OpenAI also introduced Fast mode for the API, replacing its Priority Processing option. For GPT-5.6 Sol, OpenAI reports that Fast mode offers up to 2.5 times the speed of Standard processing at twice the price, without a change in model intelligence. API requests already tagged priority will automatically use Fast mode, according to the company.
OpenAI describes Luna as its lowest-cost GPT-5.6 option and Terra as a balanced model for everyday workloads. The company stated that Luna can use tools and complete multi-step workflows, while the pricing changes extend to usage accounting in Codex and ChatGPT Work.
Cost implications for teams
The cuts materially change the token-cost profile for teams routing high-volume work through OpenAI's API, particularly where model selection is driven by throughput, tool use, and output-token expense. At the listed rates, Luna's input and output prices are one tenth of Terra's.
Across comparable model platforms, lower inference prices can make it more practical to increase evaluation sample sizes, use multi-step agent workflows, and reserve higher-cost models for tasks that demonstrably require them. Teams evaluating the update can compare quality, latency, tool-call reliability, and total output-token consumption rather than treating the per-token reduction as a standalone performance measure.
Key Points
- 1OpenAI reduced GPT-5.6 Terra and Luna API prices, lowering the operating cost of workloads using those two model tiers.
- 2ChatGPT Work and Codex users receive more Terra and Luna usage within existing subscription limits through revised usage accounting.
- 3Fast mode replaces Priority Processing for GPT-5.6 Sol, offering a higher-cost latency option with backward compatibility for priority-tagged requests.
Scoring Rationale
The pricing changes affect API economics and subscription usage for OpenAI customers using GPT-5.6 Terra and Luna. They are especially relevant to practitioners operating high-volume inference and agentic workflows, although this is a pricing and service-tier update rather than a new model release.
Sources
Primary source and supporting public references used for this report.
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