Claude Opus 4.5 Pro vs Claude Sonnet 4.5 Max: which model should you choose?
We compared Claude Opus 4.5 Pro and Claude Sonnet 4.5 Max on price, context window and 12 benchmarks. Claude Opus 4.5 Pro has the stronger average benchmark score; Claude Opus 4.5 Pro is cheaper on a blended 3:1 basis.
Claude Opus 4.5 Pro
Claude Opus 4.5 Pro is a frontier model from Anthropic. It offers a 200,000-token context window, costs $20.98 per million input tokens and $85.59 per million output tokens, and averages 89.1 across the index's benchmark suite.
- Input
- $20.98 / 1M
- Output
- $85.59 / 1M
- Context
- 200,000
- Avg score
- 89.1
- Open weights
- No
Claude Sonnet 4.5 Max
Claude Sonnet 4.5 Max is a frontier model from Anthropic. It offers a 1,000,000-token context window, costs $19.90 per million input tokens and $95.47 per million output tokens, and averages 87.2 across the index's benchmark suite.
- Input
- $19.90 / 1M
- Output
- $95.47 / 1M
- Context
- 1,000,000
- Avg score
- 87.2
- Open weights
- No
Specification comparison
| Spec | Claude Opus 4.5 Pro | Claude Sonnet 4.5 Max | Edge |
|---|---|---|---|
| Input price / 1M | $20.98 | $19.90 | B |
| Output price / 1M | $85.59 | $95.47 | A |
| Context window | 200,000 | 1,000,000 | B |
| Max output | 32,768 | 65,536 | B |
| Average score | 89.1 | 87.2 | A |
| Arena Elo | 1483.9 | 1474.9 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Claude Opus 4.5 Pro wins 10, Claude Sonnet 4.5 Max wins 2, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude Opus 4.5 Pro | Claude Sonnet 4.5 Max | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 91.2 | 86.1 | 5.1 | Claude Opus 4.5 Pro |
| GPQA Diamond | 86.0 | 84.4 | 1.6 | Claude Opus 4.5 Pro |
| SWE-bench Verified | 81.1 | 80.2 | 0.9 | Claude Opus 4.5 Pro |
| HumanEval | 93.4 | 92.4 | 1.0 | Claude Opus 4.5 Pro |
| MATH-500 | 91.2 | 92.8 | 1.6 | Claude Sonnet 4.5 Max |
| AIME 2025 | 91.4 | 85.4 | 6.0 | Claude Opus 4.5 Pro |
| LiveCodeBench | 84.1 | 82.8 | 1.3 | Claude Opus 4.5 Pro |
| IFEval | 96.1 | 92.9 | 3.2 | Claude Opus 4.5 Pro |
| TruthfulQA | 86.7 | 87.3 | 0.6 | Claude Sonnet 4.5 Max |
| HellaSwag | 95.2 | 93.1 | 2.1 | Claude Opus 4.5 Pro |
| MMMU | 83.3 | 82.0 | 1.3 | Claude Opus 4.5 Pro |
| Arena Elo | 1483.9 | 1474.9 | 9.0 | Claude Opus 4.5 Pro |
Price analysis
On a blended 3:1 input-to-output basis, Claude Opus 4.5 Pro costs about $37.13 per million tokens and Claude Sonnet 4.5 Max costs about $38.79. Claude Opus 4.5 Pro is roughly 4% cheaper than Claude Sonnet 4.5 Max. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Claude Sonnet 4.5 Max has the larger context window at 1,000,000 tokens, compared with 200,000 for Claude Opus 4.5 Pro. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude Opus 4.5 Pro wins 10, Claude Sonnet 4.5 Max wins 2, and 0 are tied. On the index average, Claude Opus 4.5 Pro leads Claude Sonnet 4.5 Max by 1.9 points (89.1 versus 87.2).
The price picture favours Claude Opus 4.5 Pro. The context picture favours Claude Sonnet 4.5 Max. 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 Opus 4.5 Pro for quality-sensitive work, and check whether its price holds at your expected volume before committing.
Choose Claude Opus 4.5 Pro if
- You want the higher average benchmark score in this index.
- Unit cost matters and you want the cheaper blended price.
Choose Claude Sonnet 4.5 Max if
- You need the larger 1,000,000-token context window.
- You need the larger 65,536-token output limit.
FAQ
Is Claude Opus 4.5 Pro better than Claude Sonnet 4.5 Max?
On the index average, Claude Opus 4.5 Pro leads Claude Sonnet 4.5 Max by 1.9 points (89.1 versus 87.2). The better choice depends on price, context and your task. Claude Opus 4.5 Pro wins 10 benchmarks, Claude Sonnet 4.5 Max wins 2.
Which is cheaper, Claude Opus 4.5 Pro or Claude Sonnet 4.5 Max?
Claude Opus 4.5 Pro is cheaper on a blended 3:1 basis at about $37.13 per million tokens, versus $38.79 for Claude Sonnet 4.5 Max.
Which has the larger context window?
Claude Sonnet 4.5 Max has the larger context window at 1,000,000 tokens. Claude Opus 4.5 Pro has 200,000 tokens.
Are these models open weights?
Claude Opus 4.5 Pro is proprietary; Claude Sonnet 4.5 Max is proprietary.
Which should I choose for production?
If you need a single default, start with Claude Opus 4.5 Pro for quality-sensitive work, and check whether its price holds at your expected volume before committing.