OpenAI · Model
GPT-6 Luna pricing, context window and specs
GPT-6 Luna costs $0.10 per million input tokens and $0.50 per million output tokens, and reads up to 1,050,000 tokens per request. By blended price it is number 6 of 60 from cheapest in OpenAI's current line-up.
- Input / 1M
- $0.10
- Output / 1M
- $0.50
- Cached / 1M
- $0.01
- Context
- 1,050,000
- Max output
- 128,000
- Released
- 2026-09-22
Estimate your cost with GPT-6 LunaCompare all OpenAI modelsCount tokens for GPT-6 Luna
Pricing
GPT-6 Luna API pricing
| Price per 1M tokens | Input | Output |
|---|---|---|
| Standard | $0.10 | $0.50 |
| Cached input (read) | $0.01 | – |
| Batch API | $0.05 | $0.25 |
| Prompts of 272,000+ tokens | $0.20 | $0.75 |
Output costs 5.0× the input price, so long replies drive the bill more than long prompts. If your requests share a long fixed prefix, such as a system prompt or tool definitions, caching cuts that part to 10% of the normal input price. Once a single prompt reaches 272,000 tokens, the whole request is billed at the higher long-context rate shown above.
Examples
What GPT-6 Luna costs in practice
| Workload | Tokens in / out | Requests/day | Per request | Per month |
|---|---|---|---|---|
| Support chatbot50% cached | 1,500 / 400 | 1,000 | $0.000283 | $8.59 |
| RAG app20% cached | 6,000 / 500 | 500 | $0.000742 | $11.28 |
| Coding agent80% cached | 40,000 / 2,000 | 200 | $0.00212 | $12.90 |
| Document summariserbatch | 8,000 / 600 | 300 | $0.00055 | $5.02 |
Change any number in the cost calculator.
Context
Context window
GPT-6 Luna accepts up to 1,050,000 tokens per request, roughly 787,500 English words or 1,575 pages. That budget is shared between your prompt and the reply, and a single reply is capped at 128,000 tokens.
Filling the whole window with one prompt costs about $0.21 at list price, so for repeated long-document work, retrieval (sending only the relevant parts) or prompt caching is usually much cheaper.
Features
Capabilities
- Image input
- Yes
- Tool / function calling
- Yes
- Reasoning mode
- Yes
- Prompt caching
- Yes
- Structured output
- Yes
- Open weights
- No
- Accepts
- file, image, text
- Knowledge cutoff
- Not published
As declared by the provider’s API. It shows a feature exists, not how well it works.
OpenAI
Where GPT-6 Luna sits in OpenAI’s line-up
Ranked by blended price (three parts input to one part output, $0.20 per 1M for GPT-6 Luna), it is number 6 of 60 from cheapest of OpenAI’s 60 priced models. See every OpenAI model and price
| Model | Input / 1M | Output / 1M | Context | Released |
|---|---|---|---|---|
| GPT-6.1 Sol | $2 | $10 | 1,050,000 | 2026-09-29 |
| GPT-6.1 Sol Pro | $2 | $10 | 1,050,000 | 2026-09-29 |
| GPT-6 Luna (this page) | $0.10 | $0.50 | 1,050,000 | 2026-09-22 |
| GPT-6 Luna Pro | $0.10 | $0.50 | 1,050,000 | 2026-09-22 |
| GPT-6 Sol | $2 | $10 | 1,050,000 | 2026-09-22 |
| GPT-6 Sol Pro | $2 | $10 | 1,050,000 | 2026-09-22 |
| GPT-6 Astra | $10 | $50 | 1,050,000 | 2026-09-04 |
| GPT-6 Astra Pro | $10 | $50 | 1,050,000 | 2026-09-04 |
Save
Cheaper alternatives
- Qwen3.7 FlashQwen73% cheaper
- Seed 1.6 FlashByteDance Seed34% cheaper
Current models from major providers, one per provider, that keep image input, tool calling, a reasoning mode, a usable context window and output limit. Compared by blended price.
Compare
Similarly priced models
- Claude Haiku 5.5Anthropic$0.10 / $0.50
- Ministral 3 14B 2512Mistral$0.20 / $0.20
- Qwen3 VL 8B InstructQwen$0.117 / $0.455
- Seed-2.0-MiniByteDance Seed$0.10 / $0.40
- Nemotron 3 SuperNVIDIA$0.08 / $0.45
Current models from other major providers, closest blended price.
FAQ
GPT-6 Luna questions
How much does GPT-6 Luna cost?
GPT-6 Luna costs $0.10 per million input tokens and $0.50 per million output tokens, with cached input at $0.01. A typical chatbot reply (1,500 tokens in, 400 out) costs about $0.00035. Use the LLM cost calculator for your own workload.
What is GPT-6 Luna's context window?
1,050,000 tokens, about 787,500 English words or 1,575 printed pages, shared between your prompt and the reply. A single reply can be up to 128,000 tokens.
Does GPT-6 Luna support prompt caching and batch requests?
Yes, cached input is billed at $0.01 per million tokens (10% of the normal input price). A batch API is available at $0.05 input and $0.25 output per million tokens.
What are cheaper alternatives to GPT-6 Luna?
With the same essentials (image input and tool calling), the cheapest options are Qwen3.7 Flash (73% cheaper), Seed 1.6 Flash (34% cheaper). Cheaper doesn't mean equivalent, so test them on your own prompts.
Is GPT-6 Luna open source?
No, GPT-6 Luna is only available through OpenAI's API and partners; its weights aren't published.