ChatGPT 6 Luna ⌄

Ask ChatGPT 6 Luna

OpenAI's most efficient GPT-6 model.

Two-sentence answer Short and direct

Sort and tag Returned as a table

Tighten this text Same facts, fewer words

Ten quick ideas Fast brainstorm

About ChatGPT 6 Luna — examples and limitations

GPT-6 Luna is OpenAI's most efficient model for focused, high-volume tasks, released September 22, 2026. On OpenAI's factuality test it makes fewer errors than GPT-5.6 Sol (7.6% vs 8.4%), which OpenAI says it does at about a hundredth of the cost. Its long-context recall has not been published.

ChatGPT 6 Luna at a glance

Provider	OpenAI
Access on AskAI.free	Premium model; the 7-day Pro trial unlocks access.
Best first test	Quick questions and short replies where speed beats depth
Model position	New model in the OpenAI family.

What makes ChatGPT 6 Luna different

GPT-6 Luna is the quick-turn member of the GPT-6 family, tuned for short, repeatable work rather than long reasoning. Its factual accuracy has overtaken GPT-5.6 Sol on OpenAI's test, but no long-document recall score exists yet, so long inputs remain Sol or Astra territory. It carries the lightest allowance weight of any GPT-6 model here.

What ChatGPT 6 Luna is best for

Quick questions and short replies where speed beats depth
Repeated, high-volume jobs: tagging, sorting, rewording, extraction
Short coding help - 66.6% on DeepSWE against GPT-5.6 Luna's 62.2%
Everyday facts, with 7.6% of answers containing an error vs 12.0% for GPT-5.6 Luna
The most recent training data in the GPT-6 family, up to May 18, 2026

How to use ChatGPT 6 Luna

Step 1 Keep prompts short and specific. Luna is built for focused tasks, and its long-context recall is unmeasured, so move long material to GPT-6 Sol or Astra.

Step 2 State the length you want. Independent testing found Luna verbose, and a word limit keeps replies quick to read.

Step 3 Use it for batches of small jobs - rewording, classification, quick lookups - where its speed adds up across many messages.

Example prompts

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Frequently asked questions

What is GPT-6 Luna?

Luna is the smallest and cheapest GPT-6 model, released on September 22, 2026 alongside GPT-6 Sol. OpenAI calls it its most efficient model for focused, high-volume tasks and trained it with methods similar to GPT-6 Astra.

What changed from GPT-5.6 Luna?

Clearly better on accuracy and coding: 7.6% vs 12.0% on OpenAI's factual-error test, 66.6% vs 62.2% on DeepSWE and 42.4% vs 39.8% on FrontierCode. On OSWorld computer use the two are level at 52.7%.

Can Luna handle long documents?

Nobody knows yet. OpenAI has not published a long-context recall score for GPT-6 Luna, and GPT-5.6 Luna managed only 41.3% on MRCR. Until it is measured, use GPT-6 Sol or Astra for anything long.

How fast is Luna?

Artificial Analysis measured about 146 tokens per second at maximum effort, well ahead of GPT-6 Sol's 86. It also found Luna verbose, so ask for short answers when that is what you want.

Is Luna in ChatGPT?

At launch OpenAI offered Luna in ChatGPT's Work and Codex modes (free accounts only in the desktop app) and said it was not yet available in Chat. Here you can chat with it directly on a Pro plan.

Do I need Pro for Luna?

Yes, Luna is part of the Pro plan. Starting the 7-day free trial gives you access straight away, with no charge until the trial ends.

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