GPT-6 Luna API Pricing
GPT-6 Luna is OpenAI's high-volume tier, released September 22, 2026 at $0.10/M input, $0.01/M cached input and $0.50/M output — half the GPT-5.6 Luna card of $0.20 / $1.20, on the same 1.05M context window as the rest of the GPT-6 family. Prompts over 272K input tokens bill on the long-context card at $0.20/M and $0.75/M.
Run the numbers.
Live calculator pre-loaded with GPT-6 Luna's standard short-context rates. This is the tier to route bulk work to: at $0.10/M input it is a twentieth of GPT-6.1 Sol, and the cache read costs $0.01/M. Reasoning effort runs from none to max and bills as output.
Real-world presets.
Repo-wide architecture migration
Multi-step diligence brief
Reading 150-page contracts
Executive workflow turn
Counted with the o200k_base BPE encoding — the same tokenizer the API uses — entirely in your browser. The encoder loads on your first keystroke (~1 MB, one time); your text never leaves this page.
| Model | Input /M | Output /M | Effective blended | Context | Best for |
|---|---|---|---|---|---|
| GPT-6 Luna Current | $0.10 cache $0.01 | $0.50 | $0.0682 agentic 92/8 | 1.05M | High-volume and routing work |
| GPT-6.1 Sol | $2.00 cache $0.10 | $10.00 | $1.29 +19× | 1.05M | Coding and long-running agents |
| GPT-6 Astra | $10.00 cache $1.00 | $50.00 | $6.82 +100× | 1.05M | OpenAI's top-of-stack reasoning tier |
| GPT-5.6 Sol | $4.00 cache $0.40 | $20.00 | $2.73 +40× · promo | 1.05M | The Daybreak-programme Sol, still listed |
| Claude Opus 5.5 | $4.00 cache $0.20 | $20.00 | $2.58 +38× | 1M | Anthropic's frontier alternative |
| Grok 4.7 | $2.00 cache $0.50 | $6.00 | $1.19 +17× | 500K | Cheaper frontier coding model |
| Gemini 3.8 Flash | $0.75 cache $0.075 | $3.75 | $0.481 +7.0× · promo | 1M | Multimodal high-volume alternative |
Compare siblings
Frequently asked.
GPT-6 Luna pricing questions - the cheapest current OpenAI card, and where the cheap tier stops being cheap.
Q · 01 How much does GPT-6 Luna cost? +
gpt-6-luna at $0.10/M input, $0.01/M cached input, $0.125/M cache writes and $0.50/M output for prompts up to 272K input tokens.Q · 02 Is it cheaper than GPT-5.6 Luna? +
$0.10 / $0.50 against $0.20 / $1.20, and the cache read drops from $0.02/M to $0.01/M. Blended at our standard mix that is $0.0682/M against $0.152/M.Q · 03 How does it compare with GPT-6.1 Sol? +
$0.10 / $0.50 against $2.00 / $10.00 — on the same 1.05M context window. Route the volume here and the hard work to GPT-6.1 Sol; the arithmetic of that split is on our routing-by-complexity post.Q · 04 When does long-context pricing apply? +
272K input tokens, where the whole request bills at $0.20/M input, $0.02/M cached input and $0.75/M output. On a cheap tier that step matters more in relative terms than it does on Sol.Q · 05 How much cheaper are Batch and Flex? +
$0.05/M input and $0.25/M output. Fast mode runs at double standard instead.Q · 06 What is the context window? +
1.05M tokens with 128K max output and a knowledge cutoff of May 18, 2026 — the same window as GPT-6 Sol and GPT-6 Astra. Text and image input, text output.