Claude Haiku 4.5 vs Sonar Pro Reasoning: which model should you choose?
We compared Claude Haiku 4.5 and Sonar Pro Reasoning on price, context window and 12 benchmarks. Sonar Pro Reasoning has the stronger average benchmark score; Sonar Pro Reasoning is cheaper on a blended 3:1 basis.
Claude Haiku 4.5
Claude Haiku 4.5 is a multimodal model from Anthropic. It offers a 1,000,000-token context window, costs $13.86 per million input tokens and $74.67 per million output tokens, and averages 79.4 across the index's benchmark suite.
- Input
- $13.86 / 1M
- Output
- $74.67 / 1M
- Context
- 1,000,000
- Avg score
- 79.4
- Open weights
- No
Sonar Pro Reasoning
Sonar Pro Reasoning is a multimodal model from Perplexity. It offers a 128,000-token context window, costs $13.94 per million input tokens and $72.76 per million output tokens, and averages 80.5 across the index's benchmark suite.
- Input
- $13.94 / 1M
- Output
- $72.76 / 1M
- Context
- 128,000
- Avg score
- 80.5
- Open weights
- No
Specification comparison
| Spec | Claude Haiku 4.5 | Sonar Pro Reasoning | Edge |
|---|---|---|---|
| Input price / 1M | $13.86 | $13.94 | A |
| Output price / 1M | $74.67 | $72.76 | B |
| Context window | 1,000,000 | 128,000 | A |
| Max output | 128,000 | 32,768 | A |
| Average score | 79.4 | 80.5 | B |
| Arena Elo | 1421.8 | 1439.7 | B |
| Open weights | No | No | Tie |
Benchmark comparison
Claude Haiku 4.5 wins 4, Sonar Pro Reasoning wins 8, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude Haiku 4.5 | Sonar Pro Reasoning | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 84.1 | 82.6 | 1.5 | Claude Haiku 4.5 |
| GPQA Diamond | 74.1 | 76.2 | 2.1 | Sonar Pro Reasoning |
| SWE-bench Verified | 69.2 | 71.7 | 2.5 | Sonar Pro Reasoning |
| HumanEval | 84.7 | 82.7 | 2.0 | Claude Haiku 4.5 |
| MATH-500 | 81.4 | 85.1 | 3.7 | Sonar Pro Reasoning |
| AIME 2025 | 76.5 | 73.7 | 2.8 | Claude Haiku 4.5 |
| LiveCodeBench | 71.6 | 75.6 | 4.0 | Sonar Pro Reasoning |
| IFEval | 85.2 | 87.1 | 1.9 | Sonar Pro Reasoning |
| TruthfulQA | 79.6 | 84.4 | 4.8 | Sonar Pro Reasoning |
| HellaSwag | 89.6 | 89.9 | 0.3 | Sonar Pro Reasoning |
| MMMU | 77.6 | 76.1 | 1.5 | Claude Haiku 4.5 |
| Arena Elo | 1421.8 | 1439.7 | 17.9 | Sonar Pro Reasoning |
Price analysis
On a blended 3:1 input-to-output basis, Claude Haiku 4.5 costs about $29.06 per million tokens and Sonar Pro Reasoning costs about $28.65. Sonar Pro Reasoning is roughly 1% cheaper than Claude Haiku 4.5. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Claude Haiku 4.5 has the larger context window at 1,000,000 tokens, compared with 128,000 for Sonar Pro Reasoning. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude Haiku 4.5 wins 4, Sonar Pro Reasoning wins 8, and 0 are tied. On the index average, Sonar Pro Reasoning leads Claude Haiku 4.5 by 1.1 points (80.5 versus 79.4).
The price picture favours Sonar Pro Reasoning. The context picture favours Claude Haiku 4.5. 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 Sonar Pro Reasoning for quality-sensitive work, and check whether its price holds at your expected volume before committing.
Choose Claude Haiku 4.5 if
- You need the larger 1,000,000-token context window.
- You need the larger 128,000-token output limit.
Choose Sonar Pro Reasoning if
- You want the higher average benchmark score in this index.
- Unit cost matters and you want the cheaper blended price.
- The workload needs multi-step reasoning.
FAQ
Is Claude Haiku 4.5 better than Sonar Pro Reasoning?
On the index average, Sonar Pro Reasoning leads Claude Haiku 4.5 by 1.1 points (80.5 versus 79.4). The better choice depends on price, context and your task. Claude Haiku 4.5 wins 4 benchmarks, Sonar Pro Reasoning wins 8.
Which is cheaper, Claude Haiku 4.5 or Sonar Pro Reasoning?
Sonar Pro Reasoning is cheaper on a blended 3:1 basis at about $28.65 per million tokens, versus $29.06 for Claude Haiku 4.5.
Which has the larger context window?
Claude Haiku 4.5 has the larger context window at 1,000,000 tokens. Sonar Pro Reasoning has 128,000 tokens.
Are these models open weights?
Claude Haiku 4.5 is proprietary; Sonar Pro Reasoning is proprietary.
Which should I choose for production?
If you need a single default, start with Sonar Pro Reasoning for quality-sensitive work, and check whether its price holds at your expected volume before committing.