Claude Haiku 4.5 vs GPT-5.6 Luna

Claude Haiku 4.5 and GPT-5.6 Luna are both current production-tier models. GPT-5.6 Luna has a 1.1M context window — about 5× the 200k of Claude Haiku 4.5. GPT-5.6 Luna leads on reasoning, general knowledge, long-context retrieval.

Specs side by side

Metric
Anthropic
Claude Haiku 4.5
OpenAI
GPT-5.6 Luna
Input price (per 1M)$1$1
Output price (per 1M)$5$6
Context window200k tokens1.1M tokens
Speed tierfastfast
Open weightsNoNo
EU regionYesYes
Free tierNoNo
Prompt cachingYesYes
Vision inputYesYes
Extended thinkingNoYes

When to choose each

Anthropic

Choose Claude Haiku 4.5 if…

  • Claude Haiku 4.5 is in the same tier as GPT-5.6 Luna — pick by provider preference or API ecosystem
OpenAI

Choose GPT-5.6 Luna if…

  • You need 1.1M context (5× more than Claude Haiku 4.5)
  • Reasoning is central to your workload
  • General knowledge is central to your workload

Benchmark delta

Claude Haiku 4.5 leads on

Claude Haiku 4.5 has no meaningful benchmark lead in this pair.

GPT-5.6 Luna leads on

  • Reasoning
  • General knowledge
  • Long-context retrieval
  • Multilingual
  • Vision

FAQ — Claude Haiku 4.5 vs GPT-5.6 Luna

Claude Haiku 4.5 vs GPT-5.6 Luna — which is better?

Claude Haiku 4.5 and GPT-5.6 Luna are both current production-tier models. GPT-5.6 Luna has a 1.1M context window — about 5× the 200k of Claude Haiku 4.5. GPT-5.6 Luna leads on reasoning, general knowledge, long-context retrieval. The right pick depends on your use case — see "When to choose each" above for a data-driven decision.

How does Claude Haiku 4.5 pricing compare to GPT-5.6 Luna?

Claude Haiku 4.5 costs $1 / $5 per 1M vs GPT-5.6 Luna at $1 / $6 per 1M. Claude Haiku 4.5 is cheaper on output tokens by roughly 20%. Both support prompt caching, which reduces effective cost by 80-90% on repeat system prompts.

Does Claude Haiku 4.5 or GPT-5.6 Luna have the bigger context window?

GPT-5.6 Luna has a 1.1M-token context window — 5× the 200k context of Claude Haiku 4.5. Enough for entire codebases, books, or multi-document RAG.

Is there a free tier for Claude Haiku 4.5 or GPT-5.6 Luna?

Claude Haiku 4.5: no — No free API tier; new accounts get starter credits. GPT-5.6 Luna: no — Low-cost at $1/$6 per 1M; starter credits only.

Which is better for coding — Claude Haiku 4.5 or GPT-5.6 Luna?

GPT-5.6 Luna leads on coding benchmarks (Claude Haiku 4.5: 82/100, GPT-5.6 Luna: 85/100). For production coding agents also weigh tool-use performance — Claude Haiku 4.5 scores 88, GPT-5.6 Luna scores 87.