GPT-5.6 Luna vs GPT-5.6 Sol
GPT-5.6 Luna and GPT-5.6 Sol are both current openai production-tier models. GPT-5.6 Luna is meaningfully cheaper at $1 / $6 per 1M. GPT-5.6 Sol leads on coding, reasoning, general knowledge.
Specs side by side
| Metric | OpenAI GPT-5.6 Luna | OpenAI GPT-5.6 Sol |
|---|---|---|
| Input price (per 1M) | $1 | $5 |
| Output price (per 1M) | $6 | $30 |
| Context window | 1.1M tokens | 1.1M tokens |
| Speed tier | fast | balanced |
| Open weights | No | No |
| EU region | Yes | Yes |
| 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 $5 / $30 per 1M)
Choose GPT-5.6 Sol if…
- You need realtime speech-to-speech
- 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.
GPT-5.6 Sol leads on
- Coding
- Reasoning
- General knowledge
- Instruction following
- Multilingual
- Vision
- Tool use
FAQ — GPT-5.6 Luna vs GPT-5.6 Sol
GPT-5.6 Luna vs GPT-5.6 Sol — which is better?
GPT-5.6 Luna and GPT-5.6 Sol are both current openai production-tier models. GPT-5.6 Luna is meaningfully cheaper at $1 / $6 per 1M. GPT-5.6 Sol 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 GPT-5.6 Sol?
GPT-5.6 Luna costs $1 / $6 per 1M vs GPT-5.6 Sol at $5 / $30 per 1M. GPT-5.6 Luna is cheaper on output tokens by roughly 400%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.
Does GPT-5.6 Luna or GPT-5.6 Sol have the bigger context window?
GPT-5.6 Sol has a 1.1M-token context window — 1× the 1.1M context of GPT-5.6 Luna. Enough for entire codebases, books, or multi-document RAG.
Is there a free tier for GPT-5.6 Luna or GPT-5.6 Sol?
GPT-5.6 Luna: no — Low-cost at $1/$6 per 1M; starter credits only. GPT-5.6 Sol: no — Paid-only — no free API tier; available via ChatGPT Plus/Pro.
Which is better for coding — GPT-5.6 Luna or GPT-5.6 Sol?
GPT-5.6 Sol leads on coding benchmarks (GPT-5.6 Luna: 85/100, GPT-5.6 Sol: 96/100). For production coding agents also weigh tool-use performance — GPT-5.6 Luna scores 87, GPT-5.6 Sol scores 95.