Kimi K3 vs GPT-6 Luna
GPT-6 Luna is 15.8× cheaper for typical traffic ; Kimi K3 scores higher on the Artificial Analysis intelligence index (43.6 vs 38.1).
Prices checked Oct 21, 2026
| Kimi K3 | GPT-6 Luna | |
|---|---|---|
| Developer | Moonshot AI | OpenAI |
| Input / 1M tokens | $0.239 | $0.10 |
| Output / 1M tokens | $11.94 | $0.50 |
| Cached input / 1M | $0.21 | $0.01 |
| Context window | 1.05M | 1.05M |
| Max output | 944K | 128K |
| Intelligence index | 43.6 | 38.1 |
| Image input | Yes | Yes |
| Tool calling | Yes | Yes |
| Reasoning mode | Yes | Yes |
| Open weights | Yes | No |
Monthly cost for common workloads
| Workload | Kimi K3 | GPT-6 Luna |
|---|---|---|
| Customer chatbot 1,000 conversations a day, 8 turns each | $1,082 | $58.56 |
| Document Q&A (RAG) 500 questions a day over retrieved documents | $111 | $11.94 |
| Coding / tool-using agent 200 tasks a day, long tool-heavy contexts | $365 | $23.70 |
| Content generation 30 long articles a day | $27.50 | $1.40 |
| Classification / extraction 100,000 short items a day | $752 | $112 |
Estimates include cached-input discounts where a model offers them. Try your own numbers in the cost calculator.
Which one to choose
- Lowest cost: GPT-6 Luna — 15.8× cheaper on a 3:1 input/output mix.
- Longer documents: GPT-6 Luna reads up to 1.05M tokens at once.
- Capabilities: Kimi K3 — vision, tools, reasoning, JSON, open weights; GPT-6 Luna — vision, tools, reasoning, JSON.