OpenAI · Released Jul 9, 2026GPT-5.6 Luna
Cost-efficient GPT-5.6 model for fast, high-volume workloads.
- Capability
- 156.5ECI · #21 of 148
- Input
- $0.20per 1M tokens
- Output
- $1.20per 1M tokens
- Context
- 1.05M128K max output
What it costs
- Input
- $0.20per million tokens
- Output
- $1.20per million tokens
- Cached input
- $0.02per million tokens
- Cache write
- $0.25per million tokens
- Over 272K tokens
- $0.40 / $1.80input / output per million
- Blended (3:1)
- $0.45cheaper than 63% of priced models
Typical monthly bills
| Monthly usage | Estimated cost |
|---|---|
| Side project2M input + 0.5M output tokens | $1.00 |
| Team assistant25M input + 5M output tokens | $11.00 |
| Production app250M input + 50M output tokens | $110.00 |
Official OpenAI API price, as listed on models.dev.
Independent benchmarks
#21 of 148 scored models
The shaded band is Epoch AI’s confidence range (154.1–158.6); the tick marks the median scored model.
Scores from Epoch AI, run independently of OpenAI.
The details
- Lab
- OpenAI
- Released
- Jul 9, 2026
- Knowledge cutoff
- Feb 16, 2026
- Context window
- 1,050,000 tokens
- Max output
- 128,000 tokens
- Inputs
- Text, Images, PDFs
- Output
- Text
- Reasoning
- Adjustable effort low · medium · high · xhigh · max
- Tool calling
- Yes
- Structured output
- Yes
- Weights
- Proprietary
- API model ID
gpt-5.6-lunaon OpenAI- Availability
- 38 API providerslisted on models.dev
What OpenAI claims
Published by the lab at launch. Settings vary, so compare these only with care.
| Benchmark | Score | Setting | Source |
|---|---|---|---|
| SWE-Bench Pro | 62.7 resolve rate | — | Source |
| Terminal-Bench v2.1 | 84.7 success rate | — | Source |
| DeepSWE v1.1 | 67.2 resolve rate | — | Source |
| GPQA Diamond | 92.3 | — | Source |
| FrontierMath vv2 | 78.6 | — | Source |
| BrowseComp | 83.3 | — | Source |
| OSWorld v2.0 | 45.6 success rate | — | Source |
| MMMU Pro | 78.4 | no tools | Source |
| Agents' Last Exam | 50.3 | — | Source |
| Toolathlon | 53.4 success rate | — | Source |
| Artificial Analysis Intelligence Index v4.1 | 51.2 | max | Source |
| Artificial Analysis Coding Agent Index v1.1 | 74.6 | max | Source |
More from OpenAI
About GPT-5.6 Luna
How much does GPT-5.6 Luna cost?
GPT-5.6 Luna costs $0.20 input / $1.20 output per million tokens (official OpenAI API price). Cached input is $0.02 per million tokens, and writing to the cache costs $0.25. Requests over 272K tokens are billed at $0.40 input / $1.80 output. At a 3:1 input-to-output mix that is $0.45 per million tokens, cheaper than 63% of the 360 priced models we track.
What is the context window of GPT-5.6 Luna?
GPT-5.6 Luna accepts up to 1,050,000 tokens per request and can write up to 128,000 tokens in one response.
How good is GPT-5.6 Luna?
Epoch AI gives GPT-5.6 Luna a Capabilities Index score of 156.5 (likely range 154.1–158.6), ranking it #21 of 148 models Epoch has scored. Epoch AI benchmark results: GPQA Diamond 91.6%, FrontierMath Tiers 1–3 82.1%, OTIS Mock AIME 2024–2025 98.3%, SimpleQA Verified 41.0%.
Is GPT-5.6 Luna open source?
No. GPT-5.6 Luna is proprietary; you use it through OpenAI’s API or partner platforms.
What inputs does GPT-5.6 Luna support?
GPT-5.6 Luna accepts text, images and PDFs and replies in text. It is a reasoning model with low, medium, high, xhigh and max effort settings, supports tool calling and can return structured JSON output.
When was GPT-5.6 Luna released?
OpenAI released GPT-5.6 Luna on Jul 9, 2026. Its training data runs to Feb 16, 2026.
What are the best alternatives to GPT-5.6 Luna?
The closest current models from other labs on capability, price and release date are DeepSeek V4.1 Flash (DeepSeek, ECI 155.0, $0.15 / $0.60), Gemini 3.8 Flash (Google, ECI 156.9, $0.75 / $3.75), GLM-5.3-Flash (Z.ai (Zhipu), ECI 151.9, $0.15 / $0.50) and Inkling Small (Thinking Machines, ECI 150.2, $0.50 / $1.20).