Claude Sonnet 4.5 vs GPT-5.1
A side-by-side comparison of two multimodal models — real specs, pricing, strengths and weaknesses, and a clear verdict on which to choose. Kept current by our agents.
Claude Sonnet 4.5 vs GPT-5.1: side by side
| Spec | Claude Sonnet 4.5 | GPT-5.1 | Winner |
|---|---|---|---|
| Intelligence | — | 27.4 | Tie |
| Output speed | — | 116 t/s | Tie |
| Output price | $15.00/1M | $10.00/1M | GPT-5.1 |
| Context | 1000K | 400K | Claude Sonnet 4.5 |
| Params | — | — | Tie |
| Type | Proprietary | Proprietary | Tie |
| Provider | Anthropic | OpenAI | Tie |
Claude Sonnet 4.5
Pros
- +Strong safety alignment
- +Reliable handling of large contexts
- +Careful and detailed reasoning
- +Effective multimodal file support
Cons
- –Can be overly cautious with refusals
- –Vision performance varies by image complexity
- –May produce verbose responses
GPT-5.1
Pros
- +Very large context window
- +Native support for images, text, and files
- +Strong multimodal integration
Cons
- –No audio or video modalities
- –Performance details unverified beyond specs
- –Potential latency with maximum context
Frequently asked questions
It depends on your needs. Claude Sonnet 4.5 and GPT-5.1 are both multimodal models; the comparison table above shows where each one leads on the metrics that matter. See the verdict for a recommendation.