Claude Opus 4.5 Vision vs Claude Sonnet 4.5: which model should you choose?
We compared Claude Opus 4.5 Vision and Claude Sonnet 4.5 on price, context window and 12 benchmarks. Claude Sonnet 4.5 has the stronger average benchmark score; Claude Sonnet 4.5 is cheaper on a blended 3:1 basis.
Claude Opus 4.5 Vision
Claude Opus 4.5 Vision is a frontier model from Anthropic. It offers a 200,000-token context window, costs $17.70 per million input tokens and $74.84 per million output tokens, and averages 85.9 across the index's benchmark suite.
- Input
- $17.70 / 1M
- Output
- $74.84 / 1M
- Context
- 200,000
- Avg score
- 85.9
- Open weights
- No
Claude Sonnet 4.5
Claude Sonnet 4.5 is a frontier model from Anthropic. It offers a 400,000-token context window, costs $17.84 per million input tokens and $70.50 per million output tokens, and averages 86.0 across the index's benchmark suite.
- Input
- $17.84 / 1M
- Output
- $70.50 / 1M
- Context
- 400,000
- Avg score
- 86.0
- Open weights
- No
Specification comparison
| Spec | Claude Opus 4.5 Vision | Claude Sonnet 4.5 | Edge |
|---|---|---|---|
| Input price / 1M | $17.70 | $17.84 | A |
| Output price / 1M | $74.84 | $70.50 | B |
| Context window | 200,000 | 400,000 | B |
| Max output | 32,768 | 128,000 | B |
| Average score | 85.9 | 86.0 | B |
| Arena Elo | 1452.2 | 1478.2 | B |
| Open weights | No | No | Tie |
Benchmark comparison
Claude Opus 4.5 Vision wins 4, Claude Sonnet 4.5 wins 8, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude Opus 4.5 Vision | Claude Sonnet 4.5 | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 86.9 | 88.0 | 1.1 | Claude Sonnet 4.5 |
| GPQA Diamond | 80.7 | 82.6 | 1.9 | Claude Sonnet 4.5 |
| SWE-bench Verified | 77.7 | 74.2 | 3.5 | Claude Opus 4.5 Vision |
| HumanEval | 88.2 | 92.7 | 4.5 | Claude Sonnet 4.5 |
| MATH-500 | 91.9 | 87.0 | 4.9 | Claude Opus 4.5 Vision |
| AIME 2025 | 85.4 | 86.3 | 0.9 | Claude Sonnet 4.5 |
| LiveCodeBench | 80.1 | 82.5 | 2.4 | Claude Sonnet 4.5 |
| IFEval | 92.6 | 91.1 | 1.5 | Claude Opus 4.5 Vision |
| TruthfulQA | 86.9 | 87.2 | 0.3 | Claude Sonnet 4.5 |
| HellaSwag | 91.4 | 93.0 | 1.6 | Claude Sonnet 4.5 |
| MMMU | 83.2 | 80.9 | 2.3 | Claude Opus 4.5 Vision |
| Arena Elo | 1452.2 | 1478.2 | 26.0 | Claude Sonnet 4.5 |
Price analysis
On a blended 3:1 input-to-output basis, Claude Opus 4.5 Vision costs about $31.98 per million tokens and Claude Sonnet 4.5 costs about $31.00. Claude Sonnet 4.5 is roughly 3% cheaper than Claude Opus 4.5 Vision. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Claude Sonnet 4.5 has the larger context window at 400,000 tokens, compared with 200,000 for Claude Opus 4.5 Vision. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude Opus 4.5 Vision wins 4, Claude Sonnet 4.5 wins 8, and 0 are tied. On the index average, Claude Sonnet 4.5 leads Claude Opus 4.5 Vision by 0.1 points (86.0 versus 85.9).
The price picture favours Claude Sonnet 4.5. The context picture favours Claude Sonnet 4.5. 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 Claude Sonnet 4.5 for quality-sensitive work, and check whether its price holds at your expected volume before committing.
Choose Claude Opus 4.5 Vision if
- You prefer Anthropic's tooling or already use it.
Choose Claude Sonnet 4.5 if
- You want the higher average benchmark score in this index.
- Unit cost matters and you want the cheaper blended price.
- You need the larger 400,000-token context window.
- You need the larger 128,000-token output limit.
FAQ
Is Claude Opus 4.5 Vision better than Claude Sonnet 4.5?
On the index average, Claude Sonnet 4.5 leads Claude Opus 4.5 Vision by 0.1 points (86.0 versus 85.9). The better choice depends on price, context and your task. Claude Opus 4.5 Vision wins 4 benchmarks, Claude Sonnet 4.5 wins 8.
Which is cheaper, Claude Opus 4.5 Vision or Claude Sonnet 4.5?
Claude Sonnet 4.5 is cheaper on a blended 3:1 basis at about $31.00 per million tokens, versus $31.98 for Claude Opus 4.5 Vision.
Which has the larger context window?
Claude Sonnet 4.5 has the larger context window at 400,000 tokens. Claude Opus 4.5 Vision has 200,000 tokens.
Are these models open weights?
Claude Opus 4.5 Vision is proprietary; Claude Sonnet 4.5 is proprietary.
Which should I choose for production?
If you need a single default, start with Claude Sonnet 4.5 for quality-sensitive work, and check whether its price holds at your expected volume before committing.