Claude Sonnet 4.5 Turbo vs Grok 4: which model should you choose?
We compared Claude Sonnet 4.5 Turbo and Grok 4 on price, context window and 12 benchmarks. Grok 4 has the stronger average benchmark score; Claude Sonnet 4.5 Turbo 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
Grok 4 is a frontier model from xAI. It offers a 200,000-token context window, costs $17.90 per million input tokens and $84.75 per million output tokens, and averages 86.5 across the index's benchmark suite.
- Input
- $17.90 / 1M
- Output
- $84.75 / 1M
- Context
- 200,000
- Avg score
- 86.5
- Open weights
- No
Specification comparison
| Spec | Claude Sonnet 4.5 Turbo | Grok 4 | Edge |
|---|---|---|---|
| Input price / 1M | $18.37 | $17.90 | B |
| Output price / 1M | $81.65 | $84.75 | A |
| Context window | 1,000,000 | 200,000 | A |
| Max output | 65,536 | 32,768 | A |
| Average score | 85.9 | 86.5 | B |
| Arena Elo | 1461.7 | 1457.8 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Claude Sonnet 4.5 Turbo wins 4, Grok 4 wins 7, and 1 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude Sonnet 4.5 Turbo | Grok 4 | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 87.2 | 87.8 | 0.6 | Grok 4 |
| GPQA Diamond | 83.7 | 82.6 | 1.1 | Claude Sonnet 4.5 Turbo |
| SWE-bench Verified | 75.2 | 77.9 | 2.7 | Grok 4 |
| HumanEval | 90.4 | 92.0 | 1.6 | Grok 4 |
| MATH-500 | 88.0 | 90.8 | 2.8 | Grok 4 |
| AIME 2025 | 87.8 | 82.2 | 5.6 | Claude Sonnet 4.5 Turbo |
| LiveCodeBench | 78.9 | 82.2 | 3.3 | Grok 4 |
| IFEval | 91.4 | 91.6 | 0.2 | Grok 4 |
| TruthfulQA | 87.7 | 87.6 | 0.1 | Claude Sonnet 4.5 Turbo |
| HellaSwag | 93.9 | 93.9 | 0.0 | Tie |
| MMMU | 81.1 | 82.9 | 1.8 | Grok 4 |
| Arena Elo | 1461.7 | 1457.8 | 3.9 | Claude Sonnet 4.5 Turbo |
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 costs about $34.61. Claude Sonnet 4.5 Turbo is roughly 1% cheaper than Grok 4. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Claude Sonnet 4.5 Turbo has the larger context window at 1,000,000 tokens, compared with 200,000 for Grok 4. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude Sonnet 4.5 Turbo wins 4, Grok 4 wins 7, and 1 are tied. On the index average, Grok 4 leads Claude Sonnet 4.5 Turbo by 0.6 points (86.5 versus 85.9).
The price picture favours Claude Sonnet 4.5 Turbo. The context picture favours Claude Sonnet 4.5 Turbo. 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 4 for quality-sensitive work and Claude Sonnet 4.5 Turbo 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
- Unit cost matters and you want the cheaper blended price.
- You need the larger 1,000,000-token context window.
- You need the larger 65,536-token output limit.
Choose Grok 4 if
- You want the higher average benchmark score in this index.
FAQ
Is Claude Sonnet 4.5 Turbo better than Grok 4?
On the index average, Grok 4 leads Claude Sonnet 4.5 Turbo by 0.6 points (86.5 versus 85.9). The better choice depends on price, context and your task. Claude Sonnet 4.5 Turbo wins 4 benchmarks, Grok 4 wins 7.
Which is cheaper, Claude Sonnet 4.5 Turbo or Grok 4?
Claude Sonnet 4.5 Turbo is cheaper on a blended 3:1 basis at about $34.19 per million tokens, versus $34.61 for Grok 4.
Which has the larger context window?
Claude Sonnet 4.5 Turbo has the larger context window at 1,000,000 tokens. Grok 4 has 200,000 tokens.
Are these models open weights?
Claude Sonnet 4.5 Turbo is proprietary; Grok 4 is proprietary.
Which should I choose for production?
If you need a single default, start with Grok 4 for quality-sensitive work and Claude Sonnet 4.5 Turbo for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.