Claude Opus 4.5 Reasoning vs Gemini 3 Pro Max: which model should you choose?
We compared Claude Opus 4.5 Reasoning and Gemini 3 Pro Max on price, context window and 12 benchmarks. Claude Opus 4.5 Reasoning has the stronger average benchmark score; Claude Opus 4.5 Reasoning is cheaper on a blended 3:1 basis.
Claude Opus 4.5 Reasoning
Claude Opus 4.5 Reasoning is a frontier model from Anthropic. It offers a 2,000,000-token context window, costs $20.91 per million input tokens and $108.13 per million output tokens, and averages 88.2 across the index's benchmark suite.
- Input
- $20.91 / 1M
- Output
- $108.13 / 1M
- Context
- 2,000,000
- Avg score
- 88.2
- Open weights
- No
Gemini 3 Pro Max
Gemini 3 Pro Max is a frontier model from Google DeepMind. It offers a 2,000,000-token context window, costs $20.57 per million input tokens and $112.92 per million output tokens, and averages 87.9 across the index's benchmark suite.
- Input
- $20.57 / 1M
- Output
- $112.92 / 1M
- Context
- 2,000,000
- Avg score
- 87.9
- Open weights
- No
Specification comparison
| Spec | Claude Opus 4.5 Reasoning | Gemini 3 Pro Max | Edge |
|---|---|---|---|
| Input price / 1M | $20.91 | $20.57 | B |
| Output price / 1M | $108.13 | $112.92 | A |
| Context window | 2,000,000 | 2,000,000 | Tie |
| Max output | 16,384 | 128,000 | B |
| Average score | 88.2 | 87.9 | A |
| Arena Elo | 1497.5 | 1477.5 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Claude Opus 4.5 Reasoning wins 8, Gemini 3 Pro Max wins 4, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude Opus 4.5 Reasoning | Gemini 3 Pro Max | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 90.7 | 89.5 | 1.2 | Claude Opus 4.5 Reasoning |
| GPQA Diamond | 82.6 | 81.8 | 0.8 | Claude Opus 4.5 Reasoning |
| SWE-bench Verified | 79.5 | 76.6 | 2.9 | Claude Opus 4.5 Reasoning |
| HumanEval | 92.1 | 91.9 | 0.2 | Claude Opus 4.5 Reasoning |
| MATH-500 | 91.6 | 92.1 | 0.5 | Gemini 3 Pro Max |
| AIME 2025 | 88.9 | 89.6 | 0.7 | Gemini 3 Pro Max |
| LiveCodeBench | 81.8 | 83.6 | 1.8 | Gemini 3 Pro Max |
| IFEval | 95.9 | 94.7 | 1.2 | Claude Opus 4.5 Reasoning |
| TruthfulQA | 89.0 | 89.6 | 0.6 | Gemini 3 Pro Max |
| HellaSwag | 93.8 | 92.6 | 1.2 | Claude Opus 4.5 Reasoning |
| MMMU | 84.6 | 84.4 | 0.2 | Claude Opus 4.5 Reasoning |
| Arena Elo | 1497.5 | 1477.5 | 20.0 | Claude Opus 4.5 Reasoning |
Price analysis
On a blended 3:1 input-to-output basis, Claude Opus 4.5 Reasoning costs about $42.72 per million tokens and Gemini 3 Pro Max costs about $43.66. Claude Opus 4.5 Reasoning is roughly 2% cheaper than Gemini 3 Pro Max. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Both models list a 2,000,000-token context window. That is enough for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude Opus 4.5 Reasoning wins 8, Gemini 3 Pro Max wins 4, and 0 are tied. On the index average, Claude Opus 4.5 Reasoning leads Gemini 3 Pro Max by 0.3 points (88.2 versus 87.9).
The price picture favours Claude Opus 4.5 Reasoning. The context picture is effectively a tie. 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 Reasoning for quality-sensitive work, and check whether its price holds at your expected volume before committing.
Choose Claude Opus 4.5 Reasoning if
- You want the higher average benchmark score in this index.
- Unit cost matters and you want the cheaper blended price.
Choose Gemini 3 Pro Max if
- You need the larger 128,000-token output limit.
FAQ
Is Claude Opus 4.5 Reasoning better than Gemini 3 Pro Max?
On the index average, Claude Opus 4.5 Reasoning leads Gemini 3 Pro Max by 0.3 points (88.2 versus 87.9). The better choice depends on price, context and your task. Claude Opus 4.5 Reasoning wins 8 benchmarks, Gemini 3 Pro Max wins 4.
Which is cheaper, Claude Opus 4.5 Reasoning or Gemini 3 Pro Max?
Claude Opus 4.5 Reasoning is cheaper on a blended 3:1 basis at about $42.72 per million tokens, versus $43.66 for Gemini 3 Pro Max.
Which has the larger context window?
Both models list a 2,000,000-token context window.
Are these models open weights?
Claude Opus 4.5 Reasoning is proprietary; Gemini 3 Pro Max is proprietary.
Which should I choose for production?
If you need a single default, start with Claude Opus 4.5 Reasoning for quality-sensitive work, and check whether its price holds at your expected volume before committing.