Claude 3.7 Sonnet Pro vs Grok 3 Reasoning: which model should you choose?
We compared Claude 3.7 Sonnet Pro and Grok 3 Reasoning on price, context window and 12 benchmarks. Claude 3.7 Sonnet Pro has the stronger average benchmark score; Grok 3 Reasoning is cheaper on a blended 3:1 basis.
Claude 3.7 Sonnet Pro
Claude 3.7 Sonnet Pro is a frontier model from Anthropic. It offers a 128,000-token context window, costs $16.07 per million input tokens and $85.28 per million output tokens, and averages 83.3 across the index's benchmark suite.
- Input
- $16.07 / 1M
- Output
- $85.28 / 1M
- Context
- 128,000
- Avg score
- 83.3
- Open weights
- No
Grok 3 Reasoning
Grok 3 Reasoning is a frontier model from xAI. It offers a 200,000-token context window, costs $16.07 per million input tokens and $74.65 per million output tokens, and averages 82.9 across the index's benchmark suite.
- Input
- $16.07 / 1M
- Output
- $74.65 / 1M
- Context
- 200,000
- Avg score
- 82.9
- Open weights
- No
Specification comparison
| Spec | Claude 3.7 Sonnet Pro | Grok 3 Reasoning | Edge |
|---|---|---|---|
| Input price / 1M | $16.07 | $16.07 | Tie |
| Output price / 1M | $85.28 | $74.65 | B |
| Context window | 128,000 | 200,000 | B |
| Max output | 8,192 | 16,384 | B |
| Average score | 83.3 | 82.9 | A |
| Arena Elo | 1446.8 | 1448.0 | B |
| Open weights | No | No | Tie |
Benchmark comparison
Claude 3.7 Sonnet Pro wins 6, Grok 3 Reasoning wins 5, and 1 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude 3.7 Sonnet Pro | Grok 3 Reasoning | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 85.7 | 84.5 | 1.2 | Claude 3.7 Sonnet Pro |
| GPQA Diamond | 80.6 | 77.3 | 3.3 | Claude 3.7 Sonnet Pro |
| SWE-bench Verified | 71.4 | 74.0 | 2.6 | Grok 3 Reasoning |
| HumanEval | 90.0 | 88.5 | 1.5 | Claude 3.7 Sonnet Pro |
| MATH-500 | 89.2 | 90.2 | 1.0 | Grok 3 Reasoning |
| AIME 2025 | 81.5 | 78.2 | 3.3 | Claude 3.7 Sonnet Pro |
| LiveCodeBench | 74.1 | 76.5 | 2.4 | Grok 3 Reasoning |
| IFEval | 88.5 | 90.2 | 1.7 | Grok 3 Reasoning |
| TruthfulQA | 86.0 | 83.4 | 2.6 | Claude 3.7 Sonnet Pro |
| HellaSwag | 89.7 | 89.7 | 0.0 | Tie |
| MMMU | 79.7 | 79.4 | 0.3 | Claude 3.7 Sonnet Pro |
| Arena Elo | 1446.8 | 1448.0 | 1.2 | Grok 3 Reasoning |
Price analysis
On a blended 3:1 input-to-output basis, Claude 3.7 Sonnet Pro costs about $33.37 per million tokens and Grok 3 Reasoning costs about $30.72. Grok 3 Reasoning is roughly 8% cheaper than Claude 3.7 Sonnet Pro. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Grok 3 Reasoning has the larger context window at 200,000 tokens, compared with 128,000 for Claude 3.7 Sonnet Pro. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude 3.7 Sonnet Pro wins 6, Grok 3 Reasoning wins 5, and 1 are tied. On the index average, Claude 3.7 Sonnet Pro leads Grok 3 Reasoning by 0.4 points (83.3 versus 82.9).
The price picture favours Grok 3 Reasoning. The context picture favours Grok 3 Reasoning. 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 3.7 Sonnet Pro for quality-sensitive work and Grok 3 Reasoning for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.
Choose Claude 3.7 Sonnet Pro if
- You want the higher average benchmark score in this index.
Choose Grok 3 Reasoning if
- Unit cost matters and you want the cheaper blended price.
- You need the larger 200,000-token context window.
- You need the larger 16,384-token output limit.
FAQ
Is Claude 3.7 Sonnet Pro better than Grok 3 Reasoning?
On the index average, Claude 3.7 Sonnet Pro leads Grok 3 Reasoning by 0.4 points (83.3 versus 82.9). The better choice depends on price, context and your task. Claude 3.7 Sonnet Pro wins 6 benchmarks, Grok 3 Reasoning wins 5.
Which is cheaper, Claude 3.7 Sonnet Pro or Grok 3 Reasoning?
Grok 3 Reasoning is cheaper on a blended 3:1 basis at about $30.72 per million tokens, versus $33.37 for Claude 3.7 Sonnet Pro.
Which has the larger context window?
Grok 3 Reasoning has the larger context window at 200,000 tokens. Claude 3.7 Sonnet Pro has 128,000 tokens.
Are these models open weights?
Claude 3.7 Sonnet Pro is proprietary; Grok 3 Reasoning is proprietary.
Which should I choose for production?
If you need a single default, start with Claude 3.7 Sonnet Pro for quality-sensitive work and Grok 3 Reasoning for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.