Comparison
Claude Haiku 4.5 vs GPT-5.1
How Claude Haiku 4.5 and GPT-5.1 compare on the numbers that decide the call - and how to switch between them without touching your code.
| Spec | Claude Haiku 4.5 | GPT-5.1 |
|---|---|---|
| Input price / 1Mlower is cheaper | $1 | $1.25 |
| Output price / 1Mlower is cheaper | $5 | $10 |
| Context windowbigger fits more | 200K | 400K |
| Typical speedfaster median | 420ms | 1.4s |
| Quality score | 84/100 | 95/100 |
| Provider | Anthropic | OpenAI |
Which should you pick?
- Claude Haiku 4.5 is cheaper on input tokens ($1 vs $1.25).
- GPT-5.1 takes a larger context window (400K tokens).
- Claude Haiku 4.5 is usually the faster to answer.
- GPT-5.1 scores higher on the composite quality benchmark.
You do not have to choose permanently. Name one as your first choice and let Final Router fall back to the other when a provider fails - the request still gets answered, and the log shows which model replied.
Common questions
- Is Claude Haiku 4.5 or GPT-5.1 cheaper?
- Claude Haiku 4.5 is cheaper on input tokens - $1 vs $1.25 per 1M. Neither is marked up: Final Router bills provider list price.
- Can I switch between Claude Haiku 4.5 and GPT-5.1 without changing my code?
- Yes. Both are called through the same OpenAI-compatible endpoint - change only the model id ("anthropic/claude-haiku-4-5" or "openai/gpt-5.1"), or let a routing policy fall back from one to the other automatically.