# Claude Sonnet 4.5 vs Kimi K2.5 (Reasoning)

> Side-by-side benchmark comparison for Claude Sonnet 4.5 and Kimi K2.5 (Reasoning) across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-sonnet-4-5-vs-kimi-k2-5-reasoning
- Last updated: October 17, 2026

- Shared sourced benchmarks: 7
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Kimi K2.5 (Reasoning) leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- Kimi K2.5 (Reasoning) has the higher overall point estimate 56.09 to 47.96. Conditional score ranges do not establish rank confidence.
- The clearest category separation is in reasoning, where the averages are 22.9 for Claude Sonnet 4.5 and 67.1 for Kimi K2.5 (Reasoning).
- The biggest single benchmark swing is Gert Labs in Agentic, with scores of 48.51% and 32.58%.
- Kimi K2.5 (Reasoning) is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- Claude Sonnet 4.5 also has the larger context window at 200K.

## Model Snapshot

| Property | Claude Sonnet 4.5 | Kimi K2.5 (Reasoning) |
|----------|----------|----------|
| Creator | Anthropic | Moonshot AI |
| Type | Proprietary | Proprietary |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 200K | 128K |
| Overall Score | 47.96 | 56.09 |
| Benchmarks Covered | 12 | 15 |
| Pricing (input/output) | $3.00 / $15.00 | $0.60 / $3.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- Claude Sonnet 4.5 public-lane score: 35.1 (Estimated · #81/128)
- Kimi K2.5 (Reasoning) public-lane score: 38.3 (Estimated · #71/128)

| Benchmark | Claude Sonnet 4.5 | Kimi K2.5 (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 50% | 50.8% | Kimi K2.5 (Reasoning) |
| OSWorld-Verified | 61.4% | 63.3% | Kimi K2.5 (Reasoning) |
| VITA-Bench | 17.0% | Coming soon | Coming soon |
| Gert Labs | 48.51% | 32.58% | Claude Sonnet 4.5 |
| JobBench | 27.7% | Coming soon | Coming soon |
| BrowseComp | Coming soon | 60.6% | Coming soon |

### Coding

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: Coming soon
- Kimi K2.5 (Reasoning) public-lane score: Coming soon

| Benchmark | Claude Sonnet 4.5 | Kimi K2.5 (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 77.2% | 76.8% | Claude Sonnet 4.5 |
| Terminal-Bench 2.0 | 50.0% | 50.8% | Kimi K2.5 (Reasoning) |
| LiveCodeBench v6 | Coming soon | 85.0% | Coming soon |
| Vibe Code Bench | Coming soon | 17.54% | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: 22.9 (Unranked · 1 rankable row)
- Kimi K2.5 (Reasoning) public-lane score: 67.1 (Unranked · 1 rankable row)

| Benchmark | Claude Sonnet 4.5 | Kimi K2.5 (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 13.6% | Coming soon | Coming soon |
| LongBench v2 | Coming soon | 61% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: Coming soon
- Kimi K2.5 (Reasoning) public-lane score: 69 (#33/54)

| Benchmark | Claude Sonnet 4.5 | Kimi K2.5 (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | Coming soon | 78.5% | Coming soon |
| CharXiv | Coming soon | 77.5% | Coming soon |

### Knowledge

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: Coming soon
- Kimi K2.5 (Reasoning) public-lane score: 48.8 (Estimated · #85/184)

| Benchmark | Claude Sonnet 4.5 | Kimi K2.5 (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 83.4% | 87.6% | Kimi K2.5 (Reasoning) |
| MMLU-Pro | Coming soon | 87.1% | Coming soon |

### Mathematics

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: 36.4 (Unranked · 2 rankable rows)
- Kimi K2.5 (Reasoning) public-lane score: Coming soon

| Benchmark | Claude Sonnet 4.5 | Kimi K2.5 (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| AIME 2025 | 87% | 96.1% | Kimi K2.5 (Reasoning) |
| FrontierMath v2 (Tiers 1-3) | 23.860% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 2.439% | Coming soon | Coming soon |
| HMMT Feb 2025 | Coming soon | 95.4% | Coming soon |

## FAQ

### Which is better overall, Claude Sonnet 4.5 or Kimi K2.5 (Reasoning)?

Kimi K2.5 (Reasoning) has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

### Where is the biggest gap between Claude Sonnet 4.5 and Kimi K2.5 (Reasoning)?

The widest category gap is in reasoning, where the averages are 22.9 for Claude Sonnet 4.5 and 67.1 for Kimi K2.5 (Reasoning).

### How many benchmarks does Claude Sonnet 4.5 cover on BenchLM?

Claude Sonnet 4.5 currently has 12 sourced benchmark scores on BenchLM.

### How many benchmarks does Kimi K2.5 (Reasoning) cover on BenchLM?

Kimi K2.5 (Reasoning) currently has 15 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Sonnet 4.5 vs Claude Sonnet 4.5 Thinking](/compare/claude-sonnet-4-5-vs-claude-sonnet-4-5-thinking)
- [Kimi K2.5 (Reasoning) vs Claude Sonnet 4.5 Thinking](/compare/claude-sonnet-4-5-thinking-vs-kimi-k2-5-reasoning)
- [Claude Sonnet 4.5 vs Kimi K2.5](/compare/claude-sonnet-4-5-vs-kimi-k2-5)
- [Kimi K2.5 (Reasoning) vs Kimi K2.5](/compare/kimi-k2-5-vs-kimi-k2-5-reasoning)

## Explore More

- [Claude Sonnet 4.5 profile](/models/claude-sonnet-4-5)
- [Kimi K2.5 (Reasoning) profile](/models/kimi-k2-5-reasoning)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)