GPT-5.6 Luna vs Kimi K3
GPT-5.6 Luna and Kimi K3 are both current production-tier models. GPT-5.6 Luna is meaningfully cheaper at $1 / $6 per 1M. Kimi K3 leads on coding, reasoning, general knowledge.
Specs side by side
| Metric | OpenAI GPT-5.6 Luna | Z.ai Kimi K3 |
|---|---|---|
| Input price (per 1M) | $1 | $3 |
| Output price (per 1M) | $6 | $15 |
| Context window | 1.1M tokens | 1.0M tokens |
| Speed tier | fast | balanced |
| Open weights | No | No |
| EU region | Yes | No |
| Free tier | No | No |
| Prompt caching | Yes | Yes |
| Vision input | Yes | Yes |
| Extended thinking | Yes | Yes |
When to choose each
Choose GPT-5.6 Luna if…
- Cost is a priority ($1 / $6 per 1M vs $3 / $15 per 1M)
- EU data residency is required
- HIPAA eligibility is required
Choose Kimi K3 if…
- Coding is central to your workload
- Reasoning is central to your workload
Benchmark delta
GPT-5.6 Luna leads on
GPT-5.6 Luna has no meaningful benchmark lead in this pair.
Kimi K3 leads on
- Coding
- Reasoning
- General knowledge
- Multilingual
FAQ — GPT-5.6 Luna vs Kimi K3
GPT-5.6 Luna vs Kimi K3 — which is better?
GPT-5.6 Luna and Kimi K3 are both current production-tier models. GPT-5.6 Luna is meaningfully cheaper at $1 / $6 per 1M. Kimi K3 leads on coding, reasoning, general knowledge. The right pick depends on your use case — see "When to choose each" above for a data-driven decision.
How does GPT-5.6 Luna pricing compare to Kimi K3?
GPT-5.6 Luna costs $1 / $6 per 1M vs Kimi K3 at $3 / $15 per 1M. GPT-5.6 Luna is cheaper on output tokens by roughly 150%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.
Does GPT-5.6 Luna or Kimi K3 have the bigger context window?
GPT-5.6 Luna has a 1.1M-token context window — 1× the 1.0M context of Kimi K3. Enough for entire codebases, books, or multi-document RAG.
Is there a free tier for GPT-5.6 Luna or Kimi K3?
GPT-5.6 Luna: no — Low-cost at $1/$6 per 1M; starter credits only. Kimi K3: no — No free API tier; kimi.com web chat is free with limits.
Which is better for coding — GPT-5.6 Luna or Kimi K3?
Kimi K3 leads on coding benchmarks (GPT-5.6 Luna: 85/100, Kimi K3: 95/100). For production coding agents also weigh tool-use performance — GPT-5.6 Luna scores 87, Kimi K3 scores 90.