Released September 22, 2026 with GPT-6 Sol. Gateway id openai/gpt-6-luna. $0.10/$0.50 per 1M up to 272K input tokens, $0.20/$0.75 above; Flex $0.05/$0.25. 1,050,000 context, 128,000 max output, knowledge cutoff May 18, 2026. Verified October 10, 2026.
$0.10/$0.50 per 1M — half of GPT-5.6 Luna's $0.20/$1.20
Flex tier at $0.05/$0.25 for batch-style work
Reasoning effort can be turned off entirely for the cheapest calls
Weaknesses
Artificial Analysis scores it 38 on its Intelligence Index, behind Claude Haiku 5.5 (43) and Gemini 3.8 Flash (41)
Prompts above 272K input tokens are billed at a higher rate
Real-world use cases
What people actually use GPT-6 Luna for.
Summarization, extraction and tagging at very high volume
Routine steps inside agent pipelines where a Sol-tier model would be overkill
Cheap first-pass coding help that a stronger model reviews
How GPT-6 Luna compares
The nearest models people weigh against it, and what actually separates them.
vs GPT-5.6 Luna — Against GPT-5.6 Luna (OpenAI), GPT-6 Luna runs about 57% cheaper per token and answers faster. Take GPT-6 Luna unless you specifically need what GPT-5.6 Luna does better.
vs Claude Haiku 5.5 — Against Claude Haiku 5.5 (Anthropic), GPT-6 Luna lands within a few percent on price and takes 1.1x the context. Which one wins depends on whether context depth or latency is your constraint.
vs GPT-6.1 Sol — Against GPT-6.1 Sol (OpenAI), GPT-6 Luna runs about 95% cheaper per token and answers faster. Take GPT-6 Luna unless you specifically need what GPT-6.1 Sol does better.
Ready to try it?
Start using GPT-6 Luna
High-volume, focused tasks where cost per call decides the model. Start free — no card required.
Anthropic's October 7, 2026 low-cost model and the first Haiku with adjustable reasoning effort — thinking can be switched off for simple requests or raised to max, at $0.10/$0.50 per 1M under 100K input tokens.
Verdict
Anthropic's budget model, now with adjustable reasoning, at $0.10/$0.50.
Quality score
82%
Pricing
$0.10/1M in
$0.50/1M out
Speed
Very fast
5/5 speed
Context
1M tokens
Announced September 28, 2026 alongside Sonnet 5.5; generally available October 7, 2026. Gateway id anthropic/claude-haiku-5.5. Tiered pricing: $0.10/$0.50 per 1M up to 100K input tokens, $0.50/$2.50 above. 1,000,000 context, 128,000 max output. Launch figures as reported by Anthropic: Terminal-Bench 4.0 39.2 (max effort), 31.6 (extra), 12.8 (low); OSWorld 2.1 offline subset 72.4 (Haiku 4.5: 15.7). Verified October 10, 2026.
BudgetFastHigh volumeSub-agentsNew
Best for
High-volume tool use, sub-agents and everyday tasks on a tight budget
OpenAI's September 29, 2026 DevDay release — a Sol-tier reasoning model that OpenAI says comes close to GPT-6 Astra on agentic coding, computer use and professional work at one fifth of Astra's price.
Verdict
Near-Astra capability at Sol pricing — OpenAI's value pick.
Quality score
95%
Pricing
$2.00/1M in
$10.00/1M out
Speed
Balanced
3/5 speed
Context
1.1M tokens
Released September 29, 2026 at OpenAI DevDay, one week after GPT-6 Sol. Gateway id openai/gpt-6.1-sol. $2/$10 per 1M up to 272K input tokens, $4/$15 above; cached input $0.10. Flex tier $1/$5; Ultrafast tier $12/$60. 1,050,000 context, 128,000 max output. OpenAI did not ship a GPT-6.1 Astra. Available to Plus, Pro, Business, Enterprise and Edu through ChatGPT Work and Codex at launch. Verified October 10, 2026.
CodingAgenticValueLong contextNew
Best for
Agentic coding and computer use when Astra's price is hard to justify
GPT-6 Luna costs $0.1 per million input tokens and $0.5 per million output tokens on the API, with cached input at $0.01 per million. A month of 10M input and 2M output tokens runs about $2.00 at list price, before any batch or caching discounts.
What is the context window of GPT-6 Luna?
GPT-6 Luna has a 1.1M tokens context window, with up to 128k tokens of output per response. That is the total of prompt plus response the model can hold in one request.
What is the knowledge cutoff of GPT-6 Luna?
GPT-6 Luna's training data runs through May 18, 2026, and the model was released on September 22, 2026. For anything after that date it needs web search or documents in the prompt.
What is GPT-6 Luna best for?
GPT-6 Luna is best for high-volume, focused tasks where cost per call decides the model. It is a strong fit when that workflow matters more than the tradeoffs around budget pricing and very fast speed.
When should I avoid GPT-6 Luna?
You are choosing a budget model from scratch — Claude Haiku 5.5 costs the same and scores higher on Artificial Analysis's index.
What is a cheaper alternative to GPT-6 Luna?
Claude Sonnet 5.5 (Anthropic) at $2.00/1M/1M input against GPT-6 Luna's $0.10/1M/1M. Near-Opus 5.5 quality on scoped work at half the price. Compare it first if GPT-6 Luna's pricing is the thing stopping you.
What is a faster alternative to GPT-6 Luna?
GPT-5.6 Luna — fast against GPT-6 Luna's very fast, with 1.1M tokens of context. Worth the swap when response time is what your users notice rather than the last few points of reasoning depth.
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