New: Lower GPT-5.6 pricing and Fast mode for Sol

Today, we’re making GPT-5.6 more affordable and faster. GPT-5.6 Luna now costs 80% less, GPT-5.6 Terra costs 20% less, and Fast mode gives API customers an option for faster access to GPT-5.6 Sol.

GPT-5.6 Luna is now 80% less expensive

Luna is our fastest and most affordable model, built to use tools and complete multi-step workflows at scale. It delivers performance comparable to models that were frontier-class a year ago at roughly 6 cents on the dollar per task, and at nearly 9 times the speed.

Luna now costs $0.20 per million input tokens and $1.20 per million output tokens.

Try GPT-5.6 Luna

GPT-5.6 Terra is now 20% less expensive

Terra, our balanced model for everyday work, now costs $2 per million input tokens and $12 per million output tokens. It balances intelligence, speed, and cost to make everyday production work more economical. If you currently default to Sol for work that doesn’t require maximum intelligence, consider evaluating Terra. 

Try GPT-5.6 Terra

Fast mode for GPT 5.6 Sol: Up to 2.5x faster responses

We’re also introducing Fast mode in the API, which replaces our Priority Processing offering. For GPT‑5.6 Sol, Fast mode now delivers up to 2.5× faster speeds than Standard processing at twice the price, with no change in intelligence. Fast mode is backward compatible: requests tagged `priority` will automatically use Fast mode. For new requests, pass `service_tier="fast"`.

Learn more about Fast mode

Making advanced intelligence more abundant, affordable, and useful is central to our mission.

Together, the GPT-5.6 family gives you a clear model for every job: Sol for the hardest problems, Terra for everyday production work, Luna for high-volume workflows.

With today’s updates, more workloads are now practical to run at scale, opening up new possibilities for what you can build.

Read the announcement

View updated API pricing