Claude Sonnet 4.5 Turbo vs Grok 4 Pro: which model should you choose?
We compared Claude Sonnet 4.5 Turbo and Grok 4 Pro on price, context window and 12 benchmarks. Claude Sonnet 4.5 Turbo has the stronger average benchmark score; Grok 4 Pro is cheaper on a blended 3:1 basis.
Claude Sonnet 4.5 Turbo
Claude Sonnet 4.5 Turbo is a frontier model from Anthropic. It offers a 1,000,000-token context window, costs $18.37 per million input tokens and $81.65 per million output tokens, and averages 85.9 across the index's benchmark suite.
- Input
- $18.37 / 1M
- Output
- $81.65 / 1M
- Context
- 1,000,000
- Avg score
- 85.9
- Open weights
- No
Grok 4 Pro
Grok 4 Pro is a frontier model from xAI. It offers a 1,000,000-token context window, costs $19.00 per million input tokens and $77.72 per million output tokens, and averages 85.4 across the index's benchmark suite.
- Input
- $19.00 / 1M
- Output
- $77.72 / 1M
- Context
- 1,000,000
- Avg score
- 85.4
- Open weights
- No
Specification comparison
| Spec | Claude Sonnet 4.5 Turbo | Grok 4 Pro | Edge |
|---|---|---|---|
| Input price / 1M | $18.37 | $19.00 | A |
| Output price / 1M | $81.65 | $77.72 | B |
| Context window | 1,000,000 | 1,000,000 | Tie |
| Max output | 65,536 | 128,000 | B |
| Average score | 85.9 | 85.4 | A |
| Arena Elo | 1461.7 | 1487.5 | B |
| Open weights | No | No | Tie |
Benchmark comparison
Claude Sonnet 4.5 Turbo wins 9, Grok 4 Pro wins 3, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude Sonnet 4.5 Turbo | Grok 4 Pro | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 87.2 | 84.9 | 2.3 | Claude Sonnet 4.5 Turbo |
| GPQA Diamond | 83.7 | 79.2 | 4.5 | Claude Sonnet 4.5 Turbo |
| SWE-bench Verified | 75.2 | 74.7 | 0.5 | Claude Sonnet 4.5 Turbo |
| HumanEval | 90.4 | 89.7 | 0.7 | Claude Sonnet 4.5 Turbo |
| MATH-500 | 88.0 | 92.3 | 4.3 | Grok 4 Pro |
| AIME 2025 | 87.8 | 85.4 | 2.4 | Claude Sonnet 4.5 Turbo |
| LiveCodeBench | 78.9 | 77.8 | 1.1 | Claude Sonnet 4.5 Turbo |
| IFEval | 91.4 | 91.3 | 0.1 | Claude Sonnet 4.5 Turbo |
| TruthfulQA | 87.7 | 86.0 | 1.7 | Claude Sonnet 4.5 Turbo |
| HellaSwag | 93.9 | 92.8 | 1.1 | Claude Sonnet 4.5 Turbo |
| MMMU | 81.1 | 84.9 | 3.8 | Grok 4 Pro |
| Arena Elo | 1461.7 | 1487.5 | 25.8 | Grok 4 Pro |
Price analysis
On a blended 3:1 input-to-output basis, Claude Sonnet 4.5 Turbo costs about $34.19 per million tokens and Grok 4 Pro costs about $33.68. Grok 4 Pro is roughly 1% cheaper than Claude Sonnet 4.5 Turbo. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Both models list a 1,000,000-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 Turbo wins 9, Grok 4 Pro wins 3, and 0 are tied. On the index average, Claude Sonnet 4.5 Turbo leads Grok 4 Pro by 0.5 points (85.9 versus 85.4).
The price picture favours Grok 4 Pro. 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 Turbo for quality-sensitive work and Grok 4 Pro for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.
Choose Claude Sonnet 4.5 Turbo if
- You want the higher average benchmark score in this index.
Choose Grok 4 Pro if
- Unit cost matters and you want the cheaper blended price.
- You need the larger 128,000-token output limit.
FAQ
Is Claude Sonnet 4.5 Turbo better than Grok 4 Pro?
On the index average, Claude Sonnet 4.5 Turbo leads Grok 4 Pro by 0.5 points (85.9 versus 85.4). The better choice depends on price, context and your task. Claude Sonnet 4.5 Turbo wins 9 benchmarks, Grok 4 Pro wins 3.
Which is cheaper, Claude Sonnet 4.5 Turbo or Grok 4 Pro?
Grok 4 Pro is cheaper on a blended 3:1 basis at about $33.68 per million tokens, versus $34.19 for Claude Sonnet 4.5 Turbo.
Which has the larger context window?
Both models list a 1,000,000-token context window.
Are these models open weights?
Claude Sonnet 4.5 Turbo is proprietary; Grok 4 Pro is proprietary.
Which should I choose for production?
If you need a single default, start with Claude Sonnet 4.5 Turbo for quality-sensitive work and Grok 4 Pro for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.