Claude 3.7 Sonnet Reasoning vs Grok 3 Pro: which model should you choose?
We compared Claude 3.7 Sonnet Reasoning and Grok 3 Pro on price, context window and 12 benchmarks. Grok 3 Pro has the stronger average benchmark score; Grok 3 Pro is cheaper on a blended 3:1 basis.
Claude 3.7 Sonnet Reasoning
Claude 3.7 Sonnet Reasoning is a frontier model from Anthropic. It offers a 128,000-token context window, costs $16.30 per million input tokens and $77.62 per million output tokens, and averages 83.7 across the index's benchmark suite.
- Input
- $16.30 / 1M
- Output
- $77.62 / 1M
- Context
- 128,000
- Avg score
- 83.7
- Open weights
- No
Grok 3 Pro
Grok 3 Pro is a frontier model from xAI. It offers a 400,000-token context window, costs $16.61 per million input tokens and $73.49 per million output tokens, and averages 83.8 across the index's benchmark suite.
- Input
- $16.61 / 1M
- Output
- $73.49 / 1M
- Context
- 400,000
- Avg score
- 83.8
- Open weights
- No
Specification comparison
| Spec | Claude 3.7 Sonnet Reasoning | Grok 3 Pro | Edge |
|---|---|---|---|
| Input price / 1M | $16.30 | $16.61 | A |
| Output price / 1M | $77.62 | $73.49 | B |
| Context window | 128,000 | 400,000 | B |
| Max output | 128,000 | 4,096 | A |
| Average score | 83.7 | 83.8 | B |
| Arena Elo | 1464.4 | 1448.4 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Claude 3.7 Sonnet Reasoning wins 5, Grok 3 Pro wins 6, and 1 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude 3.7 Sonnet Reasoning | Grok 3 Pro | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 86.4 | 83.5 | 2.9 | Claude 3.7 Sonnet Reasoning |
| GPQA Diamond | 81.3 | 81.3 | 0.0 | Tie |
| SWE-bench Verified | 71.0 | 71.4 | 0.4 | Grok 3 Pro |
| HumanEval | 89.2 | 89.9 | 0.7 | Grok 3 Pro |
| MATH-500 | 90.3 | 87.0 | 3.3 | Claude 3.7 Sonnet Reasoning |
| AIME 2025 | 79.8 | 85.5 | 5.7 | Grok 3 Pro |
| LiveCodeBench | 79.6 | 80.7 | 1.1 | Grok 3 Pro |
| IFEval | 90.1 | 88.6 | 1.5 | Claude 3.7 Sonnet Reasoning |
| TruthfulQA | 86.2 | 84.6 | 1.6 | Claude 3.7 Sonnet Reasoning |
| HellaSwag | 90.4 | 90.7 | 0.3 | Grok 3 Pro |
| MMMU | 76.5 | 78.9 | 2.4 | Grok 3 Pro |
| Arena Elo | 1464.4 | 1448.4 | 16.0 | Claude 3.7 Sonnet Reasoning |
Price analysis
On a blended 3:1 input-to-output basis, Claude 3.7 Sonnet Reasoning costs about $31.63 per million tokens and Grok 3 Pro costs about $30.83. Grok 3 Pro is roughly 3% cheaper than Claude 3.7 Sonnet Reasoning. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Grok 3 Pro has the larger context window at 400,000 tokens, compared with 128,000 for Claude 3.7 Sonnet Reasoning. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude 3.7 Sonnet Reasoning wins 5, Grok 3 Pro wins 6, and 1 are tied. On the index average, Grok 3 Pro leads Claude 3.7 Sonnet Reasoning by 0.1 points (83.8 versus 83.7).
The price picture favours Grok 3 Pro. The context picture favours Grok 3 Pro. 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 Grok 3 Pro for quality-sensitive work, and check whether its price holds at your expected volume before committing.
Choose Claude 3.7 Sonnet Reasoning if
- You need the larger 128,000-token output limit.
Choose Grok 3 Pro 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.
FAQ
Is Claude 3.7 Sonnet Reasoning better than Grok 3 Pro?
On the index average, Grok 3 Pro leads Claude 3.7 Sonnet Reasoning by 0.1 points (83.8 versus 83.7). The better choice depends on price, context and your task. Claude 3.7 Sonnet Reasoning wins 5 benchmarks, Grok 3 Pro wins 6.
Which is cheaper, Claude 3.7 Sonnet Reasoning or Grok 3 Pro?
Grok 3 Pro is cheaper on a blended 3:1 basis at about $30.83 per million tokens, versus $31.63 for Claude 3.7 Sonnet Reasoning.
Which has the larger context window?
Grok 3 Pro has the larger context window at 400,000 tokens. Claude 3.7 Sonnet Reasoning has 128,000 tokens.
Are these models open weights?
Claude 3.7 Sonnet Reasoning is proprietary; Grok 3 Pro is proprietary.
Which should I choose for production?
If you need a single default, start with Grok 3 Pro for quality-sensitive work, and check whether its price holds at your expected volume before committing.