Claude 3.7 Sonnet vs Claude Haiku 4.5 Reasoning: which model should you choose?
We compared Claude 3.7 Sonnet and Claude Haiku 4.5 Reasoning on price, context window and 12 benchmarks. Claude 3.7 Sonnet has the stronger average benchmark score; Claude Haiku 4.5 Reasoning is cheaper on a blended 3:1 basis.
Claude 3.7 Sonnet
Claude 3.7 Sonnet is a multimodal model from Anthropic. It offers a 200,000-token context window, costs $14.91 per million input tokens and $74.27 per million output tokens, and averages 81.6 across the index's benchmark suite.
- Input
- $14.91 / 1M
- Output
- $74.27 / 1M
- Context
- 200,000
- Avg score
- 81.6
- Open weights
- No
Claude Haiku 4.5 Reasoning
Claude Haiku 4.5 Reasoning is a multimodal model from Anthropic. It offers a 128,000-token context window, costs $15.11 per million input tokens and $70.05 per million output tokens, and averages 81.4 across the index's benchmark suite.
- Input
- $15.11 / 1M
- Output
- $70.05 / 1M
- Context
- 128,000
- Avg score
- 81.4
- Open weights
- No
Specification comparison
| Spec | Claude 3.7 Sonnet | Claude Haiku 4.5 Reasoning | Edge |
|---|---|---|---|
| Input price / 1M | $14.91 | $15.11 | A |
| Output price / 1M | $74.27 | $70.05 | B |
| Context window | 200,000 | 128,000 | A |
| Max output | 128,000 | 128,000 | Tie |
| Average score | 81.6 | 81.4 | A |
| Arena Elo | 1451.9 | 1444.2 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Claude 3.7 Sonnet wins 7, Claude Haiku 4.5 Reasoning wins 5, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude 3.7 Sonnet | Claude Haiku 4.5 Reasoning | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 83.5 | 83.4 | 0.1 | Claude 3.7 Sonnet |
| GPQA Diamond | 80.2 | 74.6 | 5.6 | Claude 3.7 Sonnet |
| SWE-bench Verified | 70.1 | 69.6 | 0.5 | Claude 3.7 Sonnet |
| HumanEval | 85.7 | 88.7 | 3.0 | Claude Haiku 4.5 Reasoning |
| MATH-500 | 88.9 | 85.8 | 3.1 | Claude 3.7 Sonnet |
| AIME 2025 | 81.2 | 79.0 | 2.2 | Claude 3.7 Sonnet |
| LiveCodeBench | 75.0 | 73.8 | 1.2 | Claude 3.7 Sonnet |
| IFEval | 88.5 | 89.9 | 1.4 | Claude Haiku 4.5 Reasoning |
| TruthfulQA | 81.7 | 82.5 | 0.8 | Claude Haiku 4.5 Reasoning |
| HellaSwag | 87.6 | 90.9 | 3.3 | Claude Haiku 4.5 Reasoning |
| MMMU | 75.5 | 76.7 | 1.2 | Claude Haiku 4.5 Reasoning |
| Arena Elo | 1451.9 | 1444.2 | 7.7 | Claude 3.7 Sonnet |
Price analysis
On a blended 3:1 input-to-output basis, Claude 3.7 Sonnet costs about $29.75 per million tokens and Claude Haiku 4.5 Reasoning costs about $28.84. Claude Haiku 4.5 Reasoning is roughly 3% cheaper than Claude 3.7 Sonnet. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Claude 3.7 Sonnet has the larger context window at 200,000 tokens, compared with 128,000 for Claude Haiku 4.5 Reasoning. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude 3.7 Sonnet wins 7, Claude Haiku 4.5 Reasoning wins 5, and 0 are tied. On the index average, Claude 3.7 Sonnet leads Claude Haiku 4.5 Reasoning by 0.2 points (81.6 versus 81.4).
The price picture favours Claude Haiku 4.5 Reasoning. The context picture favours Claude 3.7 Sonnet. 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 for quality-sensitive work and Claude Haiku 4.5 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 if
- You want the higher average benchmark score in this index.
- You need the larger 200,000-token context window.
Choose Claude Haiku 4.5 Reasoning if
- Unit cost matters and you want the cheaper blended price.
- The workload needs multi-step reasoning.
FAQ
Is Claude 3.7 Sonnet better than Claude Haiku 4.5 Reasoning?
On the index average, Claude 3.7 Sonnet leads Claude Haiku 4.5 Reasoning by 0.2 points (81.6 versus 81.4). The better choice depends on price, context and your task. Claude 3.7 Sonnet wins 7 benchmarks, Claude Haiku 4.5 Reasoning wins 5.
Which is cheaper, Claude 3.7 Sonnet or Claude Haiku 4.5 Reasoning?
Claude Haiku 4.5 Reasoning is cheaper on a blended 3:1 basis at about $28.84 per million tokens, versus $29.75 for Claude 3.7 Sonnet.
Which has the larger context window?
Claude 3.7 Sonnet has the larger context window at 200,000 tokens. Claude Haiku 4.5 Reasoning has 128,000 tokens.
Are these models open weights?
Claude 3.7 Sonnet is proprietary; Claude Haiku 4.5 Reasoning is proprietary.
Which should I choose for production?
If you need a single default, start with Claude 3.7 Sonnet for quality-sensitive work and Claude Haiku 4.5 Reasoning for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.