OpenAI · llm model

GPT-6 Luna

GPT-6 Luna is an OpenAI language model released Sep 22, 2026; OpenAI's newest language model in our dataset is GPT-6.1 Terra. Proprietary, API access only. OpenAI's low-cost GPT-6 model, the model behind ChatGPT Free and Go according to OpenAI. Verified against vendor sources on Oct 26, 2026.

Reported Last verified Oct 26, 2026 · All models · JSON · Markdown

ReleasedSep 22, 2026
Context window1.05M1,050,000 tokens
Max output128K128,000 tokens
LicenceProprietaryProprietary (API)

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Key facts

GPT-6 Luna: key facts with sources
Fact	Value	Source
Vendor	OpenAI	n/a
Released	Sep 22, 2026 OpenAI API changelog: GPT-6 Sol and GPT-6 Luna released together.	source
Status	generally available	n/a
API id	gpt-6-luna	source
Context window	1,050,000 tokens (1.05M)	source
Max output	128,000 tokens	source
Input	text, image	source
Output	text	source
Licence	Proprietary (API)	source
Pricing	$0.1 in / $0.5 out per 1M tokens	source

Where GPT-6 Luna sits in our data

Released Sep 22, 2026 (week 39 of 2026), in September 2026. Other models in our data released that month: GPT-6.1 Sol, Claude Sonnet 5.5, Claude Opus 5.5, Gemini 3.8 Flash TTS, Gemini 3.8 Flash-Lite TTS, GPT-6 Sol.
The previous OpenAI model we track is GPT-Live 1 (Sep 10, 2026), 12 days earlier.
Of the 60 models in our data with a published context window, GPT-6 Luna has the number 3 largest (1.05M tokens). Our data is not every model on the market.
OpenAI tools we cover: Codex CLI, ChatGPT, OpenAI Agents SDK.
All releases by date: AI model releases by month · new AI models this week. Choosing for code: best LLM for coding.

How GPT-6 Luna differs from GPT-5.6 Luna

Read from the recorded facts of the two models, not from a head-to-head test. We have not run either.

Listed price is $0.1 in and $0.5 out, against $0.2 in and $1.2 out for GPT-5.6 Luna (per 1M tokens).
Both list a 1.05M-token context window.
Both accept text, image as input.
GPT-6 Luna came out 75 days after GPT-5.6 Luna.
Facts for the other model: GPT-5.6 Luna.

Notes

Knowledge cutoff listed: May 18, 2026.

What we tested

Nothing yet. We have not run GPT-6 Luna ourselves, so every fact on this page is Reported from the sources below. When we do test it, the scope will be stated here and in our test logs. See methodology.