Claude 3.7 Sonnet Pro vs Kimi K2: which model should you choose?
We compared Claude 3.7 Sonnet Pro and Kimi K2 on price, context window and 12 benchmarks. Claude 3.7 Sonnet Pro has the stronger average benchmark score; Kimi K2 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
Kimi K2
Kimi K2 is a multimodal model from Moonshot AI. It offers a 128,000-token context window, costs $5.85 per million input tokens and $21.72 per million output tokens, and averages 83.0 across the index's benchmark suite.
- Input
- $5.85 / 1M
- Output
- $21.72 / 1M
- Context
- 128,000
- Avg score
- 83.0
- Open weights
- Yes
Specification comparison
| Spec | Claude 3.7 Sonnet Pro | Kimi K2 | Edge |
|---|---|---|---|
| Input price / 1M | $16.07 | $5.85 | B |
| Output price / 1M | $85.28 | $21.72 | B |
| Context window | 128,000 | 128,000 | Tie |
| Max output | 8,192 | 65,536 | B |
| Average score | 83.3 | 83.0 | A |
| Arena Elo | 1446.8 | 1458.5 | B |
| Open weights | No | Yes | B |
Benchmark comparison
Claude 3.7 Sonnet Pro wins 7, Kimi K2 wins 5, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Claude 3.7 Sonnet Pro | Kimi K2 | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 85.7 | 83.3 | 2.4 | Claude 3.7 Sonnet Pro |
| GPQA Diamond | 80.6 | 77.5 | 3.1 | Claude 3.7 Sonnet Pro |
| SWE-bench Verified | 71.4 | 70.2 | 1.2 | Claude 3.7 Sonnet Pro |
| HumanEval | 90.0 | 87.1 | 2.9 | Claude 3.7 Sonnet Pro |
| MATH-500 | 89.2 | 85.3 | 3.9 | Claude 3.7 Sonnet Pro |
| AIME 2025 | 81.5 | 85.1 | 3.6 | Kimi K2 |
| LiveCodeBench | 74.1 | 78.5 | 4.4 | Kimi K2 |
| IFEval | 88.5 | 91.5 | 3.0 | Kimi K2 |
| TruthfulQA | 86.0 | 84.8 | 1.2 | Claude 3.7 Sonnet Pro |
| HellaSwag | 89.7 | 92.3 | 2.6 | Kimi K2 |
| MMMU | 79.7 | 77.5 | 2.2 | Claude 3.7 Sonnet Pro |
| Arena Elo | 1446.8 | 1458.5 | 11.7 | Kimi K2 |
Price analysis
On a blended 3:1 input-to-output basis, Claude 3.7 Sonnet Pro costs about $33.37 per million tokens and Kimi K2 costs about $9.82. Kimi K2 is roughly 71% 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.
Both models list a 128,000-token context window. That is enough for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Claude 3.7 Sonnet Pro wins 7, Kimi K2 wins 5, and 0 are tied. On the index average, Claude 3.7 Sonnet Pro leads Kimi K2 by 0.3 points (83.3 versus 83.0).
The price picture favours Kimi K2. 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 3.7 Sonnet Pro for quality-sensitive work and Kimi K2 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 Kimi K2 if
- Unit cost matters and you want the cheaper blended price.
- You need the larger 65,536-token output limit.
- You need open weights for self-hosting or fine-tuning.
FAQ
Is Claude 3.7 Sonnet Pro better than Kimi K2?
On the index average, Claude 3.7 Sonnet Pro leads Kimi K2 by 0.3 points (83.3 versus 83.0). The better choice depends on price, context and your task. Claude 3.7 Sonnet Pro wins 7 benchmarks, Kimi K2 wins 5.
Which is cheaper, Claude 3.7 Sonnet Pro or Kimi K2?
Kimi K2 is cheaper on a blended 3:1 basis at about $9.82 per million tokens, versus $33.37 for Claude 3.7 Sonnet Pro.
Which has the larger context window?
Both models list a 128,000-token context window.
Are these models open weights?
Claude 3.7 Sonnet Pro is proprietary; Kimi K2 is open weights.
Which should I choose for production?
If you need a single default, start with Claude 3.7 Sonnet Pro for quality-sensitive work and Kimi K2 for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.