# GPT-6 Luna

GPT-6 Luna is an AI model released by OpenAI on Sep 22 2026. It has a 1.05M context window. Tracked results include 66.6% on DeepSWE 1.1.

## Facts

| Field | Value |
| --- | --- |
| Model | GPT-6 Luna |
| Developer | OpenAI |
| Release date | Tuesday, Sep 22 2026 |
| Licensing | Proprietary |
| Context window | 1.05M |

## API pricing

All rates in USD per 1,000,000 tokens, pay-as-you-go.

| Tier | Input | Cached input | Cache write | Output |
| --- | --- | --- | --- | --- |
| Up to 272K input tokens | $0.10 | $0.01 | $0.125 | $0.50 |
| Over 272K input tokens | $0.20 | $0.02 | $0.25 | $0.75 |

OpenAI also publishes a Fast mode for this model at exactly twice the standard rate in every column — $0.20 per million input tokens and $1.00 per million output at short context.
Verified September 22, 2026 against the first-party source: https://developers.openai.com/api/docs/pricing

## Tracked benchmark scores

| Benchmark | Score | Source | What it measures |
| --- | --- | --- | --- |
| DeepSWE 1.1 | 66.6% | Lab | Artificial Analysis' independent test of deep, agentic software-engineering work — the AI has to plan and carry out substantial coding tasks end to end. (Version 1.1 of the test.) Higher is better. |

## About GPT-6 Luna

GPT-6 Luna, released September 22, 2026, was the small model of OpenAI's GPT-6 generation, launched alongside GPT-6 Sol nineteen days after GPT-6 Astra opened the line. OpenAI's API documentation called it "our most efficient model for focused, high-volume tasks", and the launch post placed the pair as the cost-efficiency end of a family Astra still led. It launched at $0.10 per million input tokens and $0.50 per million output — down from the $0.20 and $1.20 of GPT-5.6 Luna's promotional pricing, a cut OpenAI put at 50%, and a twentieth of Sol's rate in both columns — with cached input at $0.01, cache writes at $0.125, and the family's long-context rule past 272K input tokens: double on input and cache, 1.5x on output.

The launch figures were cost-per-task arguments. At max effort it scored 66.6% on DeepSWE v1.1, which OpenAI set beside Claude Opus 5 and Claude Fable 5 at medium effort at 93% and 96% less per task; at high effort it improved on GPT-5.6 Luna by 5.4 points on AutomationBench at 58% lower cost per task, and on the offline set of OSWorld 2.0 it passed GPT-5.6 Sol at medium effort at a tenth of the cost. On OpenAI's internal factuality evaluation it matched GPT-5.6 Sol at the higher effort levels at about a hundredth of the cost.

For a model sold on price it gave up little of the family's surface: the same 1,050,000-token context window as Sol and Astra, 128,000 max output tokens, text and image input, text output, and the full reasoning-effort range from none to max with medium as the default, on the Responses, Chat Completions and Batch endpoints. Its knowledge cutoff was May 18, 2026, four weeks later than Sol's. Luna was also the one GPT-6 model that reached free users at launch: Free and Go users got it in the desktop app, while Plus, Pro, Business, Enterprise and Edu users had both models in ChatGPT Work and Codex, and the API served it as gpt-6-luna.

## Questions and answers

### When was GPT-6 Luna released?

GPT-6 Luna was released by OpenAI on Tuesday, Sep 22 2026.

### Who made GPT-6 Luna?

GPT-6 Luna was built by OpenAI. Creators of ChatGPT and the GPT series of models. Pioneered large-scale language model research.

### How much does GPT-6 Luna cost?

GPT-6 Luna costs $0.10 per million input tokens and $0.50 per million output tokens through the OpenAI API. Cached input is $0.01 per million tokens. Those are the rates for the “Up to 272K input tokens” tier; 1 other pricing tier is published for this model. Rates are pay-as-you-go API prices verified against OpenAI's published pricing on September 22, 2026.

### What benchmark scores did GPT-6 Luna get?

GPT-6 Luna reports 1 tracked benchmark score — DeepSWE 1.1: 66.6%. Tracked scores may come from lab reports or independent benchmarks; source details accompany the benchmark data.

### What is the context window of GPT-6 Luna?

GPT-6 Luna has a context window of 1.05M. That is the maximum amount of input plus output the model can hold in a single request.

### Is GPT-6 Luna open source?

No. GPT-6 Luna is a proprietary model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.

### What came before and after GPT-6 Luna?

OpenAI's previous tracked release was GPT-6 Sol on Sep 22 2026. It is the most recent OpenAI model tracked on AI Release Tracker.


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Canonical page: https://aireleasetracker.com/model/openai/gpt-6-luna
Full dataset: https://aireleasetracker.com/llms-full.txt · JSON: https://aireleasetracker.com/models.json
Source: AI Release Tracker (https://aireleasetracker.com). Most benchmark scores come from lab launch material; gathered results identify the leaderboard that published them.