OpenAI: GPT-5.6 Luna
The GPT-5.6 Luna from OpenAI is designed to handle text, file, and image inputs within a context length of 1,050,000 tokens, making it versatile for complex tasks. It supports reasoning and tools integration but does not offer structured output or open weights. This model excels in coding tasks with a perfect score of 100 on the AI Index benchmark. Given its blended benchmark score of 88.2 across three independent tests, GPT-5.6 Luna is suitable for professionals seeking robust performance and flexibility. However, at $0.2 per million input tokens and $1.2 per million output tokens, it may be cost-prohibitive for smaller projects or those on a budget, making it more appropriate for enterprises willing to invest in advanced AI capabilities.
Benchmark results
Independent, published benchmarks. Blended score 88.2 across 3 benchmarks, last refreshed 2026-08-24. How scoring works →
| Benchmark | Measures | Score |
|---|---|---|
| AI Index | broad capability composite | 86.3 |
| AI Index Coding | software engineering tasks | 100.0 |
| AI Index Agentic | multi-step tool-using tasks | 77.4 |
- Model ID
- openai/gpt-5.6-luna
- Vendor
- openai
- Released
- July 2026
- Tokenizer
- GPT
- Input Modalities
- file, image, text
- Output Modalities
- text
- Max Output
- 128,000 tokens
- Tool Calling
- ✓ supported
- Structured Output
- ✓ supported
- Reasoning Mode
- ✓ supported
- Vision
- ✓ accepts images
- Audio
- no
- Moderated
- yes
What it costs in practice
Computed from the current $0.20/M input and $1.20/M output rates. Run your own numbers →
| Job | Tokens | Cost |
|---|---|---|
| Summarize a 50-page report | 30k in / 1.5k out | under $0.01 |
| Classify 1,000 customer emails | 500k in / 50k out | $0.16 |
| A month of a busy support chatbot | 5M in / 2M out | $3.40 |
Price & spec history
Tracked daily by PicksByModel since 2026-07-17.
| Date | Input /M | Output /M | Context |
|---|---|---|---|
| 2026-08-18 | $0.20 | $1.20 | 1,050,000 |
| 2026-07-31 | $0.10 | $0.60 | 1,050,000 |
| 2026-07-28 | $0.50 | $3.00 | 1,050,000 |
| 2026-07-17 | $1.00 | $6.00 | 1,050,000 |
Strong choice for
JSON Extraction
Bulk Data Labeling
Short-Form Summarization
Email Drafting
Language Learning
Customer Support
Category rankings
Where OpenAI: GPT-5.6 Luna places across the 25 categories it ranks in. How we rank →
| # | Category | Score |
|---|---|---|
| #3 | Bulk Data LabelingData · of 25 ranked | 135 |
| #3 | Customer SupportBusiness · of 25 ranked | 135 |
| #3 | Dataset AnnotationResearch · of 25 ranked | 145 |
| #4 | JSON ExtractionData · of 25 ranked | 149 |
| #5 | Short-Form SummarizationWriting · of 25 ranked | 132 |
| #5 | Email DraftingWriting · of 25 ranked | 128 |
| #5 | Language LearningEducation · of 25 ranked | 128 |
| #5 | Chat CompanionPersonal · of 25 ranked | 132 |
| #6 | Image CaptioningVision · of 25 ranked | 121 |
| #6 | Trivia & General KnowledgePersonal · of 25 ranked | 122 |
| #10 | Sales / Cold EmailBusiness · of 25 ranked | 124 |
| #10 | Job Application DraftingBusiness · of 25 ranked | 124 |
| #10 | Journaling HelperPersonal · of 25 ranked | 124 |
| #10 | Recipe GenerationPersonal · of 25 ranked | 124 |
| #12 | Code CompletionCode · of 25 ranked | 133 |
| #17 | Regex WritingCode · of 25 ranked | 137 |
| #17 | Language TranslationWriting · of 25 ranked | 137 |
| #17 | Resume WritingBusiness · of 25 ranked | 118 |
| #17 | Tutoring for KidsPersonal · of 25 ranked | 137 |
| #18 | Meeting NotesBusiness · of 25 ranked | 152 |
| #22 | Code DocumentationCode · of 25 ranked | 143 |
| #22 | Function / Tool CallingAgents · of 25 ranked | 154 |
| #23 | SOP / Process DocsBusiness · of 25 ranked | 138 |
| #25 | CSV / Spreadsheet CleanupData · of 25 ranked | 154 |
| #25 | Screenshot DebuggingVision · of 25 ranked | 142 |
Similar models
OpenAI: GPT-5.6 Luna Pro
OpenAI: GPT-5.6 Luna Pro (batch)
OpenAI: GPT-5.6 Luna (batch)
OpenAI: GPT-5.6 Terra Pro
OpenAI: GPT-5.6 Terra Pro (batch)
OpenAI: GPT-5.6 Terra
Quick answers
- How much does OpenAI: GPT-5.6 Luna cost?
- $0.20 per million input tokens and $1.20 per million output tokens.
- What is OpenAI: GPT-5.6 Luna's context window?
- 1,050,000 tokens, roughly 1,575 pages of text in a single request.
- Does OpenAI: GPT-5.6 Luna support tool calling?
- It supports tool calling, structured output, a reasoning mode.
- Can OpenAI: GPT-5.6 Luna process images?
- Yes, it accepts image input.