GPT-6 Luna pricing
$0.10 input and $0.50 output per million tokens for prompts up to 272K tokens. Past 272K, the whole request moves to $0.20 / $0.75.
Verified 2026-10-09 against OpenAI's published rates · Compare with Haiku 5.5 in the calculator
Rates
USD per million tokens
Flex is billed like Batch. Regional processing adds 10% where available. Context: 1,050,000 tokens, up to 128K of it output. Sources: OpenAI GPT-6 Luna model page, OpenAI API pricing.
What real workloads cost
See the full comparison of the pricing cliffs and workload costs inwhy Claude Haiku 5.5 can cost up to 12× more than GPT-6 Luna.
How the 272K threshold works
OpenAI bills GPT-6 Luna at its standard rate up to 272,000 input tokens per request. Above that, the whole request moves to the long-context rate: input doubles to $0.20, output rises 1.5× to $0.75, cached input to $0.02. Because the jump is smaller and comes much later than Haiku 5.5's, Luna is usually the cheaper choice for prompts between 100K and 272K tokens.
How much does GPT-6 Luna cost?
$0.10 per million input tokens and $0.50 per million output tokens for prompts up to 272,000 tokens. Above that, the whole request is billed at $0.20 input and $0.75 output.
Does GPT-6 Luna have prompt caching?
Yes. Cached input is $0.01 per million tokens and cache writes are $0.125 per million on the standard tier ($0.02 and $0.25 above 272K).
Is there a batch or flex discount?
Yes, Batch and Flex are both half the standard price.
How large is the context window?
1,050,000 tokens, of which up to 128K can be output.
Compare before you commit
Run Luna 6 and Haiku 5.5 side by side in the playground.