Claude Sonnet 4.5 Vision vs GPT-4.1 Reasoning: which model should you choose?
We compared Claude Sonnet 4.5 Vision and GPT-4.1 Reasoning on price, context window and 12 benchmarks. Claude Sonnet 4.5 Vision and GPT-4.1 Reasoning are effectively tied on the index average; GPT-4.1 Reasoning is cheaper on a blended 3:1 basis.
Claude Sonnet 4.5 Vision
Claude Sonnet 4.5 Vision is a frontier model from Anthropic. It offers a 128,000-token context window, costs $16.99 per million input tokens and $82.33 per million output tokens, and averages 83.8 across the index's benchmark suite.
- Input
- $16.99 / 1M
- Output
- $82.33 / 1M
- Context
- 128,000
- Avg score
- 83.8
- Open weights
- No
GPT-4.1 Reasoning
GPT-4.1 Reasoning is a frontier model from OpenAI. It offers a 1,000,000-token context window, costs $16.97 per million input tokens and $82.05 per million output tokens, and averages 83.8 across the index's benchmark suite.
- Input
- $16.97 / 1M
- Output
- $82.05 / 1M
- Context
- 1,000,000
- Avg score
- 83.8
- Open weights
- No
Specification comparison
| Spec | Claude Sonnet 4.5 Vision | GPT-4.1 Reasoning | Edge |
|---|---|---|---|
| Input price / 1M | $16.99 | $16.97 | B |
| Output price / 1M | $82.33 | $82.05 | B |
| Context window | 128,000 | 1,000,000 | B |
| Max output | 16,384 | 4,096 | A |
| Average score | 83.8 | 83.8 | Tie |
| Arena Elo | 1447.6 | 1466.7 | B |
| Open weights | No | No | Tie |
Benchmark comparison
Claude Sonnet 4.5 Vision wins 5, GPT-4.1 Reasoning wins 6, and 1 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude Sonnet 4.5 Vision | GPT-4.1 Reasoning | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 84.8 | 87.3 | 2.5 | GPT-4.1 Reasoning |
| GPQA Diamond | 79.6 | 77.8 | 1.8 | Claude Sonnet 4.5 Vision |
| SWE-bench Verified | 73.7 | 73.1 | 0.6 | Claude Sonnet 4.5 Vision |
| HumanEval | 87.0 | 88.8 | 1.8 | GPT-4.1 Reasoning |
| MATH-500 | 90.6 | 89.1 | 1.5 | Claude Sonnet 4.5 Vision |
| AIME 2025 | 86.4 | 82.1 | 4.3 | Claude Sonnet 4.5 Vision |
| LiveCodeBench | 76.5 | 80.5 | 4.0 | GPT-4.1 Reasoning |
| IFEval | 89.9 | 91.6 | 1.7 | GPT-4.1 Reasoning |
| TruthfulQA | 83.7 | 84.3 | 0.6 | GPT-4.1 Reasoning |
| HellaSwag | 89.4 | 89.4 | 0.0 | Tie |
| MMMU | 79.7 | 77.5 | 2.2 | Claude Sonnet 4.5 Vision |
| Arena Elo | 1447.6 | 1466.7 | 19.1 | GPT-4.1 Reasoning |
Price analysis
On a blended 3:1 input-to-output basis, Claude Sonnet 4.5 Vision costs about $33.33 per million tokens and GPT-4.1 Reasoning costs about $33.24. GPT-4.1 Reasoning is roughly 0% cheaper than Claude Sonnet 4.5 Vision. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
GPT-4.1 Reasoning has the larger context window at 1,000,000 tokens, compared with 128,000 for Claude Sonnet 4.5 Vision. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude Sonnet 4.5 Vision wins 5, GPT-4.1 Reasoning wins 6, and 1 are tied. The two models are effectively tied on the index average at 83.8.
The price picture favours GPT-4.1 Reasoning. The context picture favours GPT-4.1 Reasoning. Those two dimensions often matter more than a few benchmark points once a model is good enough for the task.
If you need a single default, start with GPT-4.1 Reasoning; it is cheaper on a blended basis and has the larger context window. Test it on your own traffic before committing.
Choose Claude Sonnet 4.5 Vision if
- You need the larger 16,384-token output limit.
Choose GPT-4.1 Reasoning if
- Unit cost matters and you want the cheaper blended price.
- You need the larger 1,000,000-token context window.
FAQ
Is Claude Sonnet 4.5 Vision better than GPT-4.1 Reasoning?
The two models are effectively tied on the index average at 83.8. The better choice depends on price, context and your task. Claude Sonnet 4.5 Vision wins 5 benchmarks, GPT-4.1 Reasoning wins 6.
Which is cheaper, Claude Sonnet 4.5 Vision or GPT-4.1 Reasoning?
GPT-4.1 Reasoning is cheaper on a blended 3:1 basis at about $33.24 per million tokens, versus $33.33 for Claude Sonnet 4.5 Vision.
Which has the larger context window?
GPT-4.1 Reasoning has the larger context window at 1,000,000 tokens. Claude Sonnet 4.5 Vision has 128,000 tokens.
Are these models open weights?
Claude Sonnet 4.5 Vision is proprietary; GPT-4.1 Reasoning is proprietary.
Which should I choose for production?
If you need a single default, start with GPT-4.1 Reasoning; it is cheaper on a blended basis and has the larger context window. Test it on your own traffic before committing.