GPT-6 Sol and GPT-6 Luna Explained: Why They Are Not in Your ChatGPT

OpenAI released two new models on September 22, 2026, called GPT-6 Sol and GPT-6 Luna, and if you open ChatGPT looking for them you will not find them. That is not a rollout delay. OpenAI's own help page states it flatly: they "are not available in regular ChatGPT conversations." They live in two other places inside the same app, and one of those two is a software-development tool. Here is who actually gets them, and why the names make this more confusing than it needs to be.

Key Takeaways

• They are not in chat, by design. OpenAI's ChatGPT Work and Codex help page: "GPT-6 Sol and GPT-6 Luna are models for ChatGPT Work and Codex. They are not available in regular ChatGPT conversations."
• OpenAI says the same thing twice. Its release note for September 22 adds: "These models are separate from the models available in Chat." Its Codex changelog: "In ChatGPT, the models are available in Work and Codex, but not Chat."
• Paid plans get both. OpenAI: "Both models are rolling out to Plus, Pro, Business, Enterprise, and Edu users."
• Free and Go get Luna only, in the desktop app. OpenAI: "Free and Go users can access Luna in the desktop app." Its pricing page lists "GPT-6 Luna at Standard speed in the desktop app, subject to rollout" against the $0 Free plan.
• No price moved. Free is still $0, Go $8, Plus $20, Pro from $100. OpenAI says the new models run "at lower token prices than their GPT-5.6 predecessors," which is a cost to OpenAI, not a new charge to you.
• The naming is a genuine trap. GPT-5.6 Sol is the model behind paid ChatGPT chat right now. GPT-6 Sol is a different, newer model you cannot use there.
• Luna is the cheap workhorse, and its allowance shows it. On Plus, OpenAI estimates 350 to 3,000 local GPT-6 Luna messages per five-hour period, against 15 to 150 for GPT-6 Sol and 5 to 45 for GPT-6 Astra.
• This is now the named replacement for GPT-5.5. OpenAI's Models page tells Plus, Pro, Business, Enterprise and Edu users to choose GPT-6 Sol, and Free and Go users to choose GPT-6 Luna, before GPT-5.5 retires on October 14, 2026.

Do You Get GPT-6 Sol or Luna? Availability by Plan

Every consumer plan, read against OpenAI's Codex pricing page and its September 22 changelog entry on September 26, 2026. The column that matters most is the last one, because it is the same answer on every row.

Two caveats OpenAI attaches itself. First, rollout: "Availability depends on rollout and workspace settings; Enterprise administrators must enable the new models." Second, on the Free and Go row, the pricing page hedges the same way, with "subject to rollout." So a Free user may see nothing yet even in the desktop app.

What "Not in Chat" Actually Means

ChatGPT is no longer one thing, and that is the whole story here. OpenAI splits the app into Chat, Work and Codex, and the new models reach only the last two.

OpenAI's own descriptions of the three:

• Chat is for "fast, conversational assistance and everyday questions." This is the ChatGPT you already use. GPT-6 Sol and Luna are not here.
• Work is "an agent designed for longer, multi-step work and finished deliverables" -- documents, spreadsheets, presentations, reports. GPT-6 Sol and Luna are here, on paid plans.
• Codex is "dedicated to software development and technical work." GPT-6 Sol and Luna are here too, and this is the only route for Free and Go, via the desktop app.

So if you are a non-technical person paying $20 a month for ChatGPT, the honest description of what you gained on September 22 is: two new models in the tab you probably have never opened. If you are on Free, you gained one model in a desktop app built for programmers.

One further restriction worth knowing: OpenAI says "Codex is not selectable on web or mobile." That is why the Free and Go route is specifically "the desktop app" and not "ChatGPT." You have to install the Mac or Windows app to reach it at all.

The Surface List Says the Same Thing

OpenAI's Models page publishes a per-surface availability list for each model, and it is the cleanest confirmation of all of this, because it is a list of switches rather than a sentence you have to interpret. Compare GPT-6 Astra, which does reach the chat app on the right plans, with the two new models:

Astra's list has plain "ChatGPT desktop app" and "ChatGPT web" rows. The GPT-6 Sol and Luna lists do not have those rows at all. Instead they have "Work and Codex in the desktop app" and "ChatGPT Work on the web." The rows OpenAI chose to print are themselves the answer.

OpenAI's one-line descriptions of the two, for what they are meant to be good at:

• GPT-6 Sol: "Built for complex coding and agentic workflows, with stronger factual reliability and clearer communication than GPT-5.6 Sol."
• GPT-6 Luna: "Our most efficient model for focused, high-volume tasks, including summarization, extraction, and focused coding."

Both descriptions point the same way: these are work models, not conversation models. "Complex coding," "agentic workflows," "extraction" and "focused coding" is not a list of things an ordinary person does in a chat window.

Sol, Luna and Astra: Which Is Which

OpenAI now has three GPT-6 models with three different jobs and three very different appetites for your usage allowance. Its guidance, in its own words:

• Astra, "for the hardest end-to-end work." Choose it for "complete workflows across code, apps, and research that need sustained reasoning and judgment."
• Sol, "for everyday and complex work." Choose it for "ambiguous, difficult, or high-value tasks that need extra analysis, judgment, or polish."
• Luna, "for clear, repeatable tasks." Choose it "when you know what a good result looks like, such as extraction, classification, transformation, and structured summaries."

The allowance table is the clearest way to see the difference in cost. These are OpenAI's estimates of local messages per five-hour period, and they are estimates, not hard caps:

Read the Sol rows against each other and you get the practical upgrade: GPT-6 Sol gives you roughly half again as many messages as GPT-5.6 Sol on the same plan. Luna is cheap enough to run in bulk on either generation.

That table also carries a detail OpenAI does not spell out in prose: its columns are Plus, Pro 5x, Pro 20x, Standard Business and API Key. There is no Free or Go column. The free-tier route to Luna is documented on the pricing cards and in the changelog, but not in the allowance table, so OpenAI has published no estimate of how much a free user gets.

On reasoning effort, OpenAI suggests starting Sol at Medium and Luna at High, and notes one hard limit: "GPT-6 Luna supports reasoning efforts up to Max, but not Ultra."

The Naming Collision, and Why It Matters to You

This is the part that will trip people up, and it is worth being blunt about. OpenAI has now shipped two different models called Sol and two called Luna, one generation apart, and the pair you can use in ordinary chat is the older one.

So "I have Sol" and "I have Luna" are now ambiguous statements. If someone tells you ChatGPT free users got GPT-6, the accurate version is: free users can reach GPT-6 Luna inside Codex in the desktop app, subject to rollout, and their actual chat still runs GPT-5.6 Luna.

The one place the new names do reach into a decision you might have to make is the GPT-5.5 retirement on October 14, 2026. OpenAI's Models page now names the replacements by generation 6: "On Plus, Pro, Business, Enterprise, and Edu plans, choose GPT-6 Sol (gpt-6-sol) when available" and "On Free and Go plans, choose GPT-6 Luna (gpt-6-luna) in the desktop app when available." That is a change from the original September 14 notice, which named GPT-5.6 Sol. See GPT-5.5 retirement explained.

Should You Care?

Skip this entirely if you use ChatGPT for questions, writing, search or images. Nothing in your app changed on September 22, no model you use was replaced, and no price moved. The chat you type into still runs GPT-5.6.

Care if you pay for Plus or Pro and have work that produces documents. ChatGPT Work is where these models landed, and Work is the part of the product OpenAI is putting its newest models into first. If you have never opened the Work toggle, this is the release that makes it worth ten minutes.

Care if you write code, even as a hobby. On Free or Go, GPT-6 Luna in the Codex desktop app is a genuine free upgrade, and it is the only free thing in this announcement.

Do not upgrade your plan for this. Plus at $20 buys you GPT-6 Sol and Luna in Work and Codex. It does not put them in chat, and no plan does. If you were weighing whether ChatGPT Plus is worth it, this release does not move that answer.

Ignore the benchmark talk. OpenAI published no consumer-facing quality claim for these models beyond "lower token prices" and its per-task guidance. Anyone telling you GPT-6 Luna will change your everyday chatting is describing a model you cannot use there.

Sources

• OpenAI, "Codex changelog: GPT-6 Sol and Luna in Codex and ChatGPT Work", September 22, 2026
• OpenAI Help Center, "ChatGPT Release Notes", entry dated September 22, 2026
• OpenAI Help Center, "ChatGPT Work and Codex"
• OpenAI, "Models", including the GPT-5.5 retirement guidance
• OpenAI, "Pricing", plan cards and the per-plan allowance table
• OpenAI, "What's new", week of September 21-25, 2026