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OpenAI

OpenAI: GPT-6 Luna

GPT-6 Luna Overview

GPT-6 Luna is the fast, cost-efficient tier of OpenAI's GPT-6 model family, sitting below GPT-6 Sol and the larger GPT-6 Astra model that opened the generation. It is a proprietary multimodal transformer that accepts text and image input and returns text, and it exposes an adjustable reasoning effort setting so the same model can run in a low-latency mode or spend additional inference compute on harder problems. OpenAI positions it for high-volume and latency-sensitive workloads such as conversational assistants, classification, and lightweight agentic pipelines, while noting that at higher reasoning effort it handles software engineering and computer-use tasks that previously required a Sol-tier model.

The model supports a context window of roughly 1,050,000 input tokens with a maximum output of 128,000 tokens, which allows long documents, extended agent traces, and large code repositories to be processed in a single request. OpenAI describes the GPT-6 generation as improving factual reliability and adopting a more concise communication style relative to the GPT-5.6 series, and attributes the efficiency of the Sol and Luna tiers to gains in caching and inference rather than to reduced capability. Architecture details, parameter counts, and training data are not published.

GPT-6 Luna Interactive Demo

Model settings

Thinking level

Max output tokens

Default 65,536 · max 65,536

Sign in to adjust thinking and output length per run.

Results appear here. Add an image or pick an example to run GPT-6 Luna.

GPT-6 Luna Details & Performance

Details

Resources

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Vision Tasks

CaptioningChart Question AnsweringClassificationDocument Question AnsweringImage TaggingMulti-Label ClassificationOCRVision LanguageVisual Question AnsweringObject Detection

Features

Foundation VisionLLMs with Vision CapabilitiesMultimodal Vision

Usage

Past 30 Days

Performance

Avg. Latency

GPT-6 Luna Vision Evals

Vision Evals is Roboflow's ground-truth benchmark: every model runs the same real-world samples across five vision tasks, and answers are scored against ground truth.

Evals updated October 13, 2026Pricing updated October 17, 2026

Overall score#21 of 63
69.7%
Avg cost / sample#10 of 63
$0.0004
Avg speed / sample#30 of 63
10.21s
Avg tokens / sample
2.3K

Strengths and weaknesses

GPT-6 Luna averages 69.7% across the five Vision Evals tasks, ranking #21 of 63 models overall.

Its weakest relative showing is OCR, ranking #30 of 47 at 59.8%.

At $0.0004 per sample it is the 10th cheapest of the 63 benchmarked models, and its average inference time of 10.2s per sample makes it the 30th fastest.

Performance profile

Field medianGPT-6 Luna

Field medians: Object Detection 54.4%, Counting 63.5%, Identification 84.4%, OCR 63.6%, Reasoning 57.6%.

Results by task

TaskScoreField (0 to 100)RankCost / sampleSpeed
Object Detection (low)
65.5%
±0.4, Mean of 3 runs, range 65.2 to 66.0
#15 of 63$0.000615.15s
Object Detection (high)
68.0%
±0.7, Mean of 3 runs, range 67.3 to 68.6
#14 of 31$0.001421.67s
Counting (low)
71.6%
±0.0, Mean of 3 runs, range 71.6 to 71.6
#17 of 63$0.00025.68s
Counting (high)
72.1%
±0.7, Mean of 3 runs, range 71.6 to 73.0
#19 of 31$0.00048.02s
Identification (low)
87.5%
±3.1, Mean of 3 runs, range 84.4 to 90.6
#26 of 63$0.00024.72s
Identification (high)
87.5%
±3.1, Mean of 3 runs, range 84.4 to 90.6
#17 of 31$0.00024.10s
OCR (low)
59.8%
#30 of 47$0.00049.31s
Single value
41.7%
Transcription
80.0%
Structured JSON
78.2%
Text localization
47.4%
OCR (high)
62.5%
#26 of 47$0.001326.32s
Single value
44.4%
Transcription
84.0%
Structured JSON
81.0%
Text localization
50.0%
Reasoning (low)
64.2%
±3.0, Mean of 3 runs, range 60.3 to 66.2
#24 of 63$0.00038.96s
Reasoning (high)
71.1%
±2.3, Mean of 3 runs, range 68.2 to 72.8
#24 of 50$0.00047.71s
  • Thinking longer helps: 2.5 points higher on object detection at high effort for 2.3x the cost and 1.4x the latency.
  • Thinking longer helps: 0.4 points higher on counting at high effort for 1.6x the cost and 1.4x the latency.
  • Thinking longer changes nothing: the same identification score at high effort for 1.3x the cost and 0.9x the latency.
  • Thinking longer helps: 2.8 points higher on ocr at high effort for 2.9x the cost and 2.8x the latency.
  • Thinking longer helps: 6.8 points higher on reasoning at high effort for 1.7x the cost and 0.9x the latency.

Price vs. performance

Score vs. cost

Overall benchmark score against estimated cost per sample, on a log scale. Upper-left is the sweet spot: high quality at low cost.

62 models on the current benchmark · scores and efficiency pooled across all five tasks at low effort · GPT-6 Luna highlighted

GPT-6 Luna scores are the mean of 3 runs per task at both low and high effort; OCR is a single preliminary run · Methodology

View all Vision Evals →

GPT-6 Luna Pricing

GPT-6 Luna costs $0.100 per 1M input tokens and $0.500 per 1M output tokens.

Input$0.100 / 1M tokens
Output$0.500 / 1M tokens
Cached input$0.010 / 1M tokens

Pricing updated Oct 17, 2026

Alternatives to GPT-6 Luna

Other models worth comparing for similar use cases.

Google
Gemini 3.5 Flash-Lite
Gemini 3.5 Flash-Lite is a natively multimodal reasoning model developed by Google DeepMind, released on July 21, 2026 as part of the Gemini 3.5 model family. It is the fastest model in the 3.5 series, designed for both low-latency tasks and high-throughput production workloads such as agentic search, document processing, receipt translation, and large-scale data extraction. The model accepts text, images, audio, and video as inputs, with a context window of up to 1 million tokens, and produces text output. It supports configurable thinking levels, allowing developers to tune the balance between response quality, cost, and latency depending on workload requirements.On agentic and coding benchmarks, Gemini 3.5 Flash-Lite significantly outperforms its predecessor, Gemini 3.1 Flash-Lite, including on Terminal-Bench 2.1 (54% vs. 31%), GDM-MRCR v2 long-context (72.2% vs. 60.1%), and real-world task execution as measured by GDPval-AA v2 (1140 vs. 642). It also surpasses Gemini 3 Flash on SWE-Bench Pro (54.2% vs. 49.6%) and OSWorld-Verified (74.0% vs. 65.1%). According to the Artificial Analysis Index, the model generates output at approximately 350 tokens per second. It is built on the Gemini 3.5 Flash foundation and is evaluated across reasoning, coding, multimodal understanding, multilingual performance, and long-context tasks. The model is developed under Google's Frontier Safety Framework.
Anthropic
Claude Haiku 5.5
Claude Haiku 5.5 is a proprietary multimodal language model from Anthropic and the smallest member of the Claude 5.5 family, released on October 7, 2026 after Claude Opus 5.5 and Claude Sonnet 5.5. It accepts text and image input and returns text, with a 1M token context window and up to 128K output tokens per request. It is the first Haiku-class model with an adjustable effort parameter: adaptive thinking is on by default and the model decides how much to reason, steered by effort levels from low to max with medium as the default. Its training data cutoff is June 2026. Pricing starts at $0.10 per million input tokens and $0.50 per million output tokens for prompts up to 100K tokens, which Anthropic reports is about 90% lower than Claude Haiku 4.5 for requests in that range.Anthropic positions Haiku 5.5 for high-volume, latency-sensitive work such as classification, extraction, routing, summarization, and subagent tasks, and describes it as its fastest model to date at standard speed. On visual and agentic evaluations reported at launch, it scores 46.4% on Chartography, a chart reading benchmark, compared with 6.4% for Haiku 4.5 and 61.6% for Sonnet 5.5, and 72.4% on the offline subset of OSWorld 2.1, a screenshot driven computer use benchmark, compared with 15.7% for Haiku 4.5. It uses the same tokenizer as Claude Opus 4.7 and later models, so the same text counts as roughly 30% more tokens than on Haiku 4.5.
Google
Gemini 3.1 Flash-Lite
Gemini 3.1 Flash-Lite is a natively multimodal reasoning model from Google DeepMind in the Gemini 3 series, based on the Gemini 3 Pro architecture. It processes text, image, video, audio, and PDF inputs within a 1 million token context window and produces text output up to 64K tokens. The model targets high-volume, latency-sensitive workloads and supports visual question answering, image and document data extraction, content moderation, classification, translation, automated speech recognition, and agentic data pipelines. It exposes configurable thinking levels of minimal, low, medium, and high, which set the depth of internal reasoning applied per request and let developers balance response quality against cost and latency.On benchmarks reported at launch, Gemini 3.1 Flash-Lite scores 86.9% on GPQA Diamond and 76.8% on the MMMU Pro multimodal benchmark, and reaches an Elo score of 1432 on the Arena.ai leaderboard. According to Artificial Analysis benchmarks, it produces a 2.5 times faster time to first answer token and a 45% increase in output speed relative to Gemini 2.5 Flash. It also shows improved instruction following, higher audio input quality for automated speech recognition tasks, and support for structured JSON output used in data extraction pipelines.
Qwen
Qwen3.5 9b
Qwen3.5-9B is a 9-billion-parameter multimodal foundation model developed by Alibaba Cloud's Qwen team, released on March 2, 2026 as part of the Qwen3.5 model family. Designed for efficient multimodal reasoning and long-context language tasks, it notably outperforms the older Qwen3-30B, a model more than three times its size, on key benchmarks including GPQA Diamond, IFEval, and LongBench.The model supports vision-language inputs through an early-fusion multimodal architecture built on a dense hybrid foundation of Gated Delta Networks and Gated Attention. It can also operate in a text-only mode by skipping the vision encoder during inference. It provides a 262,144-token context window (extensible to ~1M tokens via YaRN) and is released under the Apache License 2.0. Within the current AI landscape, Qwen3.5-9B offers a strong balance of capability and efficiency, making it well-suited for multimodal assistants, document analysis, long-context reasoning, and developer-deployed agentic systems.
Qwen
Qwen3 VL 8B Instruct
Qwen3 VL 8B Instruct is an open-weight multimodal vision-language model developed by Qwen / Alibaba Cloud as part of the Qwen3-VL series, designed for instruction-following tasks that combine text with visual inputs such as images and video. Released around October 2025 under the Apache-2.0 license, it targets developers who need capable multimodal reasoning without the scale or cost of very large models.The model contains roughly 8.8 billion dense parameters and supports text, image, and video understanding with strong spatial perception, visual reasoning, and emerging visual agent abilities such as GUI interaction. A standout feature is its native ~256K token context window, extendable to around 1M tokens, enabling long-document reading and extended video comprehension. In today’s landscape, it balances openness, long-context capacity, and solid multimodal performance against heavier proprietary models. Typical applications include multimodal assistants, document and video analysis, visual question answering, and research or product prototyping where transparency and deployability matter.

Other OpenAI GPT Nano models

Other versions in the same family as GPT-6 Luna.

GPT-6 Luna License

Proprietary

GPT-6 Luna is proprietary: the weights are not distributed, and the GPT-6 Luna license is the vendor's commercial terms of service that you accept when you call the API.

Commercial use
Permitted under the vendor terms, typically metered per token or per request, with the vendor usage policy applying to your inputs and outputs.
Modification
Not available. GPT-6 Luna weights are closed, so you can configure prompts and use vendor-hosted fine-tuning where it is offered, but you cannot modify the model itself.
Redistribution
Not permitted. You cannot self-host or resell the model; you build on the hosted API instead.

Vendor terms govern data retention, whether your inputs can be trained on, rate limits, and regional availability, and they can change with notice. Review them if you handle regulated or customer data.

Do I need a commercial license for GPT-6 Luna?

Proprietary terms are set by the vendor rather than negotiated per project, and no open-source obligation attaches to your code. If you would rather deploy an open model instead of GPT-6 Luna, Roboflow's licensing page lists the models whose commercial license is included when you deploy on Roboflow.

Do not hesitate to reach out with questions for your commercial project — our team will help you start solving business problems on the first call. See Roboflow commercial licensing for the models included in each plan.

Talk to sales

This model is proprietary. The author retains all rights, and use of the model is governed by their specific terms of service or license agreement.

Commercial use depends on the terms set by the model author. Most proprietary commercial models require a paid subscription, API key, or per-call billing. Check the provider’s pricing and terms-of-service for details.

License information is provided as a guide and is not legal advice.

Frequently Asked Questions About GPT-6 Luna Vision

Yes. GPT-6 Luna accepts image input and handles OCR, object counting, identification, visual reasoning, and object detection. On Roboflow's Vision Evals its strongest task is Object Detection at 65.5% (#15 of 63 at low effort). You can test it on your own image in the demo above.

Yes. it scores 59.8% (#30 of 47 at low effort) on Vision Evals OCR, which covers single readings, full transcriptions, structured JSON, and locating text with boxes. Within that, full transcriptions score 80%, and returning the fields of a label or form as JSON scores 78.2%.

It's serviceable. On Vision Evals, GPT-6 Luna scores 65.5% mAP@50 on object detection (#15 of 63 at low effort) and 71.6% judge-graded accuracy on object counting.

On our benchmark's task mix, GPT-6 Luna averages $0.0004 per sample at $0.10 per 1M input and $0.50 per 1M output tokens (#10 of 63 on cost), with an average speed of 10.2s per sample across the benchmark. Actual cost depends on your images and prompts.

On the overall Vision Evals ranking, GPT-6 Luna sits #21 of 63 at 69.7%, just behind Claude Opus 5 (70.9%) and just ahead of Claude Haiku 5.5 (69.6%). See the full side-by-side: GPT-6 Luna vs Claude Opus 5.