Claude Sonnet 4 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.
Quick verdict: which should you choose?
Choose Claude Sonnet 4 if you need
- ✓Choose GPT-5.1 if you need lower output cost at $10 per million tokens.
- ✓Choose GPT-5.1 if you need measured output speed of 115.83 tokens per second.
- ✓Choose GPT-5.1 if you need a published intelligence index of 27.4.
- ✓Choose GPT-5.1 if you need a 400k context window with native image, text, and file support.
Choose GPT-5.1 if you need
- ✓Choose Claude Sonnet 4 if you need a 1M-token context window.
- ✓Choose Claude Sonnet 4 if you need strong reasoning and coherence over very long inputs.
- ✓Choose Claude Sonnet 4 if you need high-quality, detailed responses with careful safety alignment.
- ✓Choose Claude Sonnet 4 if you need effective multimodal integration on the largest context.
Verdict
GPT-5.1 leads on known speed (115.83 t/s), lower price ($10/1M), and a published intelligence index of 27.4, while Claude Sonnet 4 offers a larger 1M-token context and stronger documented reasoning over long inputs. Both provide native multimodal support for images, text, and files without audio or video. GPT-5.1 suits cost- and speed-sensitive workloads; Claude Sonnet 4 fits maximum-context coherence needs.
Claude Sonnet 4 vs GPT-5.1: side by side
| Spec | Claude Sonnet 4 | 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 |
| Params | — | — | Tie |
| Type | Proprietary | Proprietary | Tie |
| Provider | Anthropic | OpenAI | Tie |
Detailed analysis
Pricing
Winner: GPT-5.1GPT-5.1 is priced at $10 per million output tokens versus Claude Sonnet 4 at $15 per million. The $5 difference favors GPT-5.1 for high-volume usage. Both are proprietary models from major providers.
Context Window
Winner: Claude Sonnet 4Claude Sonnet 4 provides a 1M-token context while GPT-5.1 offers 400k tokens. This gives Claude Sonnet 4 an advantage for tasks requiring coherence over extremely long inputs. GPT-5.1 notes potential latency at maximum context.
Speed & Intelligence
Winner: GPT-5.1GPT-5.1 reports output speed of 115.83 t/s and an intelligence index of 27.4. Claude Sonnet 4 has no published speed or intelligence index values. Direct comparison on these metrics is therefore limited to GPT-5.1 data.
Multimodal Capabilities
Winner: TieBoth models support native multimodal integration for images, text, and files. Neither offers native audio or video modalities. Strengths are described as strong for GPT-5.1 and effective for Claude Sonnet 4.
Claude Sonnet 4
Pros
- +Strong reasoning and coherence over long inputs
- +Careful safety alignment
- +High-quality, detailed responses
- +Effective multimodal integration
Cons
- –Conservative refusals on sensitive topics
- –No native audio or video support
- –May prioritize caution over maximum helpfulness
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
Summary: Claude Sonnet 4 vs GPT-5.1
Select GPT-5.1 when speed, price, and quantified intelligence matter most. Select Claude Sonnet 4 when the largest context and long-input reasoning are primary requirements. Both remain comparable on multimodal file and image handling.
Frequently asked questions
GPT-5.1 is better on speed and price; Claude Sonnet 4 is better on context size and long-input reasoning. Neither is universally superior based on the given facts.