Claude Opus 4.8 vs GPT-5.6 Luna
Claude Opus 4.8 and GPT-5.6 Luna are both current production-tier models. GPT-5.6 Luna is meaningfully cheaper at $1 / $6 per 1M. Claude Opus 4.8 leads on coding, reasoning, general knowledge.
Specs side by side
| Metric | Anthropic Claude Opus 4.8 | OpenAI GPT-5.6 Luna |
|---|---|---|
| Input price (per 1M) | $5 | $1 |
| Output price (per 1M) | $25 | $6 |
| Context window | 1M tokens | 1.1M tokens |
| Speed tier | slow | fast |
| 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 Claude Opus 4.8 if…
- Coding is central to your workload
- Reasoning is central to your workload
Choose GPT-5.6 Luna if…
- Cost is a priority ($1 / $6 per 1M vs $5 / $25 per 1M)
- Low latency matters (fast vs slow)
Benchmark delta
Claude Opus 4.8 leads on
- Coding
- Reasoning
- General knowledge
- Long-context retrieval
- Instruction following
- Vision
- Tool use
GPT-5.6 Luna leads on
GPT-5.6 Luna has no meaningful benchmark lead in this pair.
FAQ — Claude Opus 4.8 vs GPT-5.6 Luna
Claude Opus 4.8 vs GPT-5.6 Luna — which is better?
Claude Opus 4.8 and GPT-5.6 Luna are both current production-tier models. GPT-5.6 Luna is meaningfully cheaper at $1 / $6 per 1M. Claude Opus 4.8 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 Claude Opus 4.8 pricing compare to GPT-5.6 Luna?
Claude Opus 4.8 costs $5 / $25 per 1M vs GPT-5.6 Luna at $1 / $6 per 1M. GPT-5.6 Luna is cheaper on output tokens by roughly 317%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.
Does Claude Opus 4.8 or GPT-5.6 Luna have the bigger context window?
GPT-5.6 Luna has a 1.1M-token context window — 1× the 1M context of Claude Opus 4.8. Enough for entire codebases, books, or multi-document RAG.
Is there a free tier for Claude Opus 4.8 or GPT-5.6 Luna?
Claude Opus 4.8: no — Free via Claude.ai web chat; API requires paid credits. GPT-5.6 Luna: no — Low-cost at $1/$6 per 1M; starter credits only.
Which is better for coding — Claude Opus 4.8 or GPT-5.6 Luna?
Claude Opus 4.8 leads on coding benchmarks (Claude Opus 4.8: 97/100, GPT-5.6 Luna: 85/100). For production coding agents also weigh tool-use performance — Claude Opus 4.8 scores 96, GPT-5.6 Luna scores 87.