Claude Sonnet 4.5 Reasoning vs Gemini 3 Pro Turbo: which model should you choose?
We compared Claude Sonnet 4.5 Reasoning and Gemini 3 Pro Turbo on price, context window and 12 benchmarks. Claude Sonnet 4.5 Reasoning has the stronger average benchmark score; Claude Sonnet 4.5 Reasoning is cheaper on a blended 3:1 basis.
Claude Sonnet 4.5 Reasoning
Claude Sonnet 4.5 Reasoning is a frontier model from Anthropic. It offers a 400,000-token context window, costs $19.48 per million input tokens and $68.20 per million output tokens, and averages 87.7 across the index's benchmark suite.
- Input
- $19.48 / 1M
- Output
- $68.20 / 1M
- Context
- 400,000
- Avg score
- 87.7
- Open weights
- No
Gemini 3 Pro Turbo
Gemini 3 Pro Turbo is a frontier model from Google DeepMind. It offers a 400,000-token context window, costs $19.62 per million input tokens and $89.91 per million output tokens, and averages 86.4 across the index's benchmark suite.
- Input
- $19.62 / 1M
- Output
- $89.91 / 1M
- Context
- 400,000
- Avg score
- 86.4
- Open weights
- No
Specification comparison
| Spec | Claude Sonnet 4.5 Reasoning | Gemini 3 Pro Turbo | Edge |
|---|---|---|---|
| Input price / 1M | $19.48 | $19.62 | A |
| Output price / 1M | $68.20 | $89.91 | A |
| Context window | 400,000 | 400,000 | Tie |
| Max output | 8,192 | 16,384 | B |
| Average score | 87.7 | 86.4 | A |
| Arena Elo | 1486.5 | 1494.9 | B |
| Open weights | No | No | Tie |
Benchmark comparison
Claude Sonnet 4.5 Reasoning wins 7, Gemini 3 Pro Turbo wins 4, and 1 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude Sonnet 4.5 Reasoning | Gemini 3 Pro Turbo | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 87.6 | 85.6 | 2.0 | Claude Sonnet 4.5 Reasoning |
| GPQA Diamond | 85.2 | 81.0 | 4.2 | Claude Sonnet 4.5 Reasoning |
| SWE-bench Verified | 79.6 | 77.4 | 2.2 | Claude Sonnet 4.5 Reasoning |
| HumanEval | 90.3 | 90.3 | 0.0 | Tie |
| MATH-500 | 89.7 | 92.4 | 2.7 | Gemini 3 Pro Turbo |
| AIME 2025 | 87.3 | 82.8 | 4.5 | Claude Sonnet 4.5 Reasoning |
| LiveCodeBench | 85.1 | 82.7 | 2.4 | Claude Sonnet 4.5 Reasoning |
| IFEval | 91.9 | 93.4 | 1.5 | Gemini 3 Pro Turbo |
| TruthfulQA | 87.6 | 87.8 | 0.2 | Gemini 3 Pro Turbo |
| HellaSwag | 95.2 | 94.6 | 0.6 | Claude Sonnet 4.5 Reasoning |
| MMMU | 85.2 | 82.7 | 2.5 | Claude Sonnet 4.5 Reasoning |
| Arena Elo | 1486.5 | 1494.9 | 8.4 | Gemini 3 Pro Turbo |
Price analysis
On a blended 3:1 input-to-output basis, Claude Sonnet 4.5 Reasoning costs about $31.66 per million tokens and Gemini 3 Pro Turbo costs about $37.19. Claude Sonnet 4.5 Reasoning is roughly 15% cheaper than Gemini 3 Pro Turbo. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Both models list a 400,000-token context window. That is enough for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude Sonnet 4.5 Reasoning wins 7, Gemini 3 Pro Turbo wins 4, and 1 are tied. On the index average, Claude Sonnet 4.5 Reasoning leads Gemini 3 Pro Turbo by 1.3 points (87.7 versus 86.4).
The price picture favours Claude Sonnet 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 Sonnet 4.5 Reasoning for quality-sensitive work, and check whether its price holds at your expected volume before committing.
Choose Claude Sonnet 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 Turbo if
- You need the larger 16,384-token output limit.
FAQ
Is Claude Sonnet 4.5 Reasoning better than Gemini 3 Pro Turbo?
On the index average, Claude Sonnet 4.5 Reasoning leads Gemini 3 Pro Turbo by 1.3 points (87.7 versus 86.4). The better choice depends on price, context and your task. Claude Sonnet 4.5 Reasoning wins 7 benchmarks, Gemini 3 Pro Turbo wins 4.
Which is cheaper, Claude Sonnet 4.5 Reasoning or Gemini 3 Pro Turbo?
Claude Sonnet 4.5 Reasoning is cheaper on a blended 3:1 basis at about $31.66 per million tokens, versus $37.19 for Gemini 3 Pro Turbo.
Which has the larger context window?
Both models list a 400,000-token context window.
Are these models open weights?
Claude Sonnet 4.5 Reasoning is proprietary; Gemini 3 Pro Turbo is proprietary.
Which should I choose for production?
If you need a single default, start with Claude Sonnet 4.5 Reasoning for quality-sensitive work, and check whether its price holds at your expected volume before committing.