GPT-6 Luna
OpenAI's new GPT-6 Luna model writes text and answers questions, offered to developers and not free to download.
Key facts
- Released
- Sep 22, 2026
- What it does
- Text and chat: Writes, answers questions and holds a conversation.Thinks first: Can reason step by step before it answers: slower, but better at maths, code and tricky questions.Sees images: Understands pictures, screenshots and charts you share with it.Reads files: Reads documents such as PDFs.
View moreView less
- Knowledge cutoff
- May 2026 · the latest events it learned about
- How
- For developers, through an API
- Announced as
- “Introducing GPT-6 Sol and Luna”
From trckr's archive of releases before it started watching. Date and details from Epoch AI's database of AI models (CC BY 4.0).
Price and limits
What developers pay to use it through the API: How developers plug a model into their own apps and pay per use. A model that's "in the API" can be used by programmers, even if it isn't in a chat app yet., per million Tokens: The small chunks of text a model reads and writes, about three-quarters of a word each. Prices and limits are counted in tokens. sent (input) or written back (output), and how much it can take in at once.
- Input
- $0.10
- per million tokensCached: $0.01
- Output
- $0.50
- per million tokens
- Context window: How much a model can keep in mind at once: your question, any files you share and its own replies. Measured in tokens; 1,000 tokens is about 750 words.
- 1.05M tokens
- about 790,000 words
View moreView less
- Longest answer
- 128K tokens (about 96,000 words)
- Over 272K tokens
- $0.20 input, $0.75 output per million tokens
From the lab's own listing on models.dev and OpenRouter, checked .
How it scores
From independent testers, never the lab's own claims.
- Chat answers, by people's votes#84 of 86
- Gemini 4 Carbon1,527
- 2Gemini 4 Argon1,522
- 83Qwen3.5 397B-A17B1,441
- 84GPT-6 Luna1,440
- 85DeepSeek V4 Flash 07311,439
Source: LMArena · LMArena text, adjusted for style
- Building apps, by people's votes#38 of 85
- Claude Opus 5.51,818
- 2Claude Sonnet 5.51,773
- 37DeepSeek V4 Pro 08131,581
- 38GPT-6 Luna1,577
- 39Step 5 Preview1,572
Source: LMArena · LMArena WebDev
Compare GPT-6 Luna with
It came out 19 days after GPT-6 Astra, the lab's previous model.
The details
GPT-6 Luna is OpenAI's Language model (LLM): A model trained on huge amounts of text to read and write. The engine behind chatbots like ChatGPT, Claude and Gemini. for text generation and question answering, released via API: How developers plug a model into their own apps and pay per use. A model that's "in the API" can be used by programmers, even if it isn't in a chat app yet. access only, with no size disclosed.
Model ID: The exact name developers type to use a model, like gpt-5-mini. New IDs often show up in a lab's systems before the official announcement, which is how trckr spots many releases early.
openai/gpt-6-luna-proTimeline
/OpenRouterFirst signal
Get alerts like this the moment they happen.
From OpenAI and every other major lab.