By the toolist.ai editors. Researched from public sources, not hands-on tested by toolist.ai. Updated October 27, 2026; prices checked October 21, 2026.
GPT-6 Luna: price, context window and benchmarks
GPT-6 Luna is the GPT-6 model OpenAI calls its fastest and most cost-effective, for focused, high-volume tasks, at $0.10 per million input tokens and $0.50 per million output tokens, a twentieth of GPT-6.1 Sol's price. Artificial Analysis scores it 28 on its Intelligence Index at max effort and 18 at the default medium effort.
Best for
- Focused, high-volume jobs such as summarization, extraction and focused coding, the work OpenAI's ChatGPT docs name for it
- Function calls that need no reasoning, since it accepts the "none" effort level, which GPT-6 Astra and GPT-6.1 Sol do not
- Typed answers through OpenAI's Decisions API, which launched in beta with GPT-6 Luna on October 6, 2026
- Long prompts on a small budget, with up to 922,000 input tokens and the long-context price starting only above 272,000
Key facts
| Fact | GPT-6 Luna | Source |
|---|---|---|
| Provider | OpenAI | OpenAI API docs: Pricing |
| API model name | gpt-6-luna | OpenAI API docs: GPT-6 Luna |
| Released | September 22, 2026 | OpenAI API docs: Changelog |
| Input price | $0.10 per million tokens | OpenAI API docs: Pricing |
| Cached input price | $0.01 per million tokens | OpenAI API docs: Pricing |
| Output price | $0.50 per million tokens | OpenAI API docs: Pricing |
| Context window | 1,050,000 tokens | OpenAI API docs: GPT-6 Luna |
| Maximum output | 128,000 tokens | OpenAI API docs: GPT-6 Luna |
| Knowledge cutoff | May 18, 2026 | OpenAI API docs: GPT-6 Luna |
| Input and output | Text and images in; text out | OpenAI API docs: GPT-6 Luna |
| Reasoning | Effort levels none to max; medium is the default | OpenAI API docs: GPT-6 Luna |
| API and cloud platforms | OpenAI API (Responses, Chat Completions and Batch); Chat Completions supports function calling only at the "none" effort level | OpenAI API docs: GPT-6 Luna |
| In the apps | ChatGPT Work and Codex: Free and Go get it at Standard speed in the desktop app as it rolls out, and Plus and Pro include it | ChatGPT docs: Pricing and plan access |
Prompts over 272,000 input tokens are billed at twice the input and cache rates and 1.5 times the output rate for the whole request. Cache writes cost $0.125 per million tokens (30-minute cache) or $0.25 (12-hour cache). Batch and Flex cost half; Fast mode costs double. OpenAI lists no Ultrafast price for it.
What GPT-6 Luna costs a month
Three typical workloads, priced at the standard API rates above. We calculated these; the provider does not publish them.
| Workload | Tokens a month | Cost a month |
|---|---|---|
| Support chatbot 100,000 replies, each 3,000 input and 400 output tokens, no caching | 300M in, 40M out | $50.00 |
| Document Q&A 5,000 questions over the same 60,000-token document set (90% cache hits), 800 output tokens each | 300M in, 4M out | $7.70 |
| Coding agent 200 tasks, each 1.5 million input tokens (90% cache hits) and 50,000 output tokens | 300M in, 10M out | $10.70 |
Reasoning models bill their thinking as output tokens, so heavy reasoning can raise the output count several times. Cache-write charges are not included.
Benchmarks
| Benchmark | Score | Source |
|---|---|---|
| Artificial Analysis Intelligence Index max effort | 28.0 | GPT-6 Luna (max) |
| Intelligence Index at everyday effort medium effort, the API default | 18.0 | GPT-6 Luna (medium) |
| Terminal-Bench 4.0 max effort | 13.0% | GPT-6.1 Sol vs GPT-6 Luna |
| HLE-Diamond max effort | 22.0% | GPT-6.1 Sol vs GPT-6 Luna |
| Terminal-Bench-Science 0.1 max effort | 9.0% | GPT-6.1 Sol vs GPT-6 Luna |
Speed: about 124.3 output tokens a second (max effort, Artificial Analysis; no medium-effort figure is published; GPT-6 Luna (max)).
Benchmark and speed data marked as such come from Artificial Analysis.
What changed
Compared with GPT-5.6 Luna, input falls from $0.20 to $0.10, cached input from $0.02 to $0.01 and output from $1.20 to $0.50 per million tokens. (OpenAI API docs: Pricing)
GPT-6 Luna compared
Other models
- GPT-6.1 Terra: $1 in, $5 out per million tokens
- Gemini 4 Argon: $2 in, $10 out per million tokens
- Muse Wonder: $4 in, $20 out per million tokens
- Claude Haiku 5.5: $0.10 in, $0.50 out per million tokens
- GPT-6.1 Sol: $2 in, $10 out per million tokens
- Claude Sonnet 5.5: $2 in, $10 out per million tokens
- Claude Opus 5.5: $4 in, $20 out per million tokens
- GPT-6 Sol: $2 in, $10 out per million tokens
- GPT-6 Astra: $10 in, $50 out per million tokens
- Claude Fable 5.1: $10 in, $50 out per million tokens
- Claude Opus 5: $5 in, $25 out per million tokens
All prices side by side: AI model API price table. How we research: our method.
Sources
- GPT-6.1 Sol vs GPT-6 Luna (checked 2026-10-27)
- OpenAI API docs: GPT-6 Luna (checked 2026-10-21)
- OpenAI API docs: Pricing (checked 2026-10-21)
- OpenAI API docs: Changelog (checked 2026-10-21)
- OpenAI API docs: Using GPT-6 (checked 2026-10-21)
- ChatGPT docs: Models (checked 2026-10-21)
- ChatGPT docs: Pricing and plan access (checked 2026-10-21)
- GPT-6 Luna (max) (checked 2026-10-27)
- GPT-6 Luna (medium) (checked 2026-10-27)
- OpenRouter: GPT-6 Luna (checked 2026-10-21)