Hardest reasoning tasks
Choose Kimi K3
Kimi K3 scores 43.6 on the Artificial Analysis Intelligence Index, against 37.3 for GPT-5.6 Luna.
GPT-5.6 Luna vs Kimi K3: price, context and capabilities
Choose GPT-5.6 Luna for images as input. Choose Kimi K3 for the hardest reasoning tasks, reasoning over long documents and the latest release.
In short
- A price comparison is not possible: one of them has no comparable published price.
- GPT-5.6 Luna reads more per request: 1.05M tokens against 1M.
- Only GPT-5.6 Luna offers vision, structured output, prompt caching, batch api.
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Reasoning over long documents
Choose Kimi K3
Kimi K3 scores 88.7% on Long-context reasoning (AA-LCR), against 83.7% for GPT-5.6 Luna.
Images as input
Choose GPT-5.6 Luna
GPT-5.6 Luna accepts images as input; Kimi K3 does not.
Latest release
Choose Kimi K3
Kimi K3 is the newer release (Jul 16, 2026, against Jul 9, 2026 for GPT-5.6 Luna).
Specifications side by side
| GPT-5.6 Luna | Kimi K3 | |
|---|---|---|
| Provider | OpenAI | Moonshot AI |
| Category | Language models | Language models |
| Status | Generally available | Generally available |
| Headline price | $0.45 / 1M tokens | No data |
| Input | $0.20 / 1M tokens | No data |
| Output | $1.20 / 1M tokens | No data |
| Cached input | $0.02 / 1M tokens | No data |
| Context window | 1.05M | 1M |
| Max output | 128k | No data |
| Released | Jul 9, 2026 | Jul 16, 2026 |
| Knowledge cutoff | February 2026 | No data |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Reasoning, Tool calling |
| API model id | gpt-5.6-luna | kimi-k3 |
Benchmarks side by side
Leader in bold.
| Benchmark | GPT-5.6 Luna | Kimi K3 |
|---|---|---|
| Intelligence Index | 37.3 | 43.6 |
| SciCode | 53.6% | 59.5% |
| GPQA Diamond | 91.1% | 93.5% |
| Humanity's Last Exam | 39.5% | 46.9% |
| MMMU-Pro (visual reasoning) | 78.6% | 80.5% |
| Long-context reasoning (AA-LCR) | 83.7% | 88.7% |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose GPT-5.6 Luna or Kimi K3?
Choose GPT-5.6 Luna for images as input. Choose Kimi K3 for the hardest reasoning tasks, reasoning over long documents and the latest release.
Which is cheaper, GPT-5.6 Luna or Kimi K3?
A price comparison is not possible: one of them has no comparable published price.
Which has the larger context window, GPT-5.6 Luna or Kimi K3?
GPT-5.6 Luna reads more per request: 1.05M tokens against 1M.
What is the difference between GPT-5.6 Luna and Kimi K3?
GPT-5.6 Luna is made by OpenAI and Kimi K3 by Moonshot AI. A price comparison is not possible: one of them has no comparable published price. GPT-5.6 Luna reads more per request: 1.05M tokens against 1M. Only GPT-5.6 Luna offers vision, structured output, prompt caching, batch api.
Which is newer, GPT-5.6 Luna or Kimi K3?
Kimi K3 was released on Jul 16, 2026 and GPT-5.6 Luna on Jul 9, 2026.