# Claude Sonnet 4 vs Kimi K2 (Jul 2025)

> Claude Sonnet 4 and Kimi K2 (Jul 2025) score almost the same on the Noometry Index (40.8 vs 41.2), so choose on price, context window or the category you care about most.

- Canonical page: https://noometry.com/compare/claude-sonnet-4-vs-kimi-k2
- Last updated: 2026-10-11
- Shared benchmarks: 39

## Summary

- They share 39 benchmarks with published results for both. Claude Sonnet 4 scores higher in 5 categories and Kimi K2 (Jul 2025) in 4 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in long context, where Kimi K2 (Jul 2025) leads 41.2 to 33.7.
- The biggest single-benchmark swing is Fiction.LiveBench: 46.9% for Claude Sonnet 4 and 66.7% for Kimi K2 (Jul 2025).
- Kimi K2 (Jul 2025) is cheaper at $0.57 / $2.30 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.
- Kimi K2 (Jul 2025) accepts more context: 262K tokens versus 200K.
- Kimi K2 (Jul 2025) has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| Provider | Anthropic | Moonshot AI |
| Noometry Index | 40.8 | 41.2 |
| Rank | 145 | 140 |
| Context | 200K | 262K |
| Input $/M | $3 | $0.57 |
| Output $/M | $15 | $2.30 |
| Weights | Proprietary | Open |

## Coding

- Claude Sonnet 4: 43.5 (#88)
- Kimi K2 (Jul 2025): 42.4 (#102)

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| SWE-bench Verified (bash only) | 64.9% | 63.4% |
| Aider Polyglot | 61.3% | 59.1% |
| GSO | 4.9% | 4.9% |
| WeirdML | 46.1% | 42.8% |
| LMArena Coding | 1414 | 1399 |
| ALE-Bench | 655.35 | 597.5 |
| SciCode | 40% | — |

## Agentic & Tool Use

- Claude Sonnet 4: 38.5 (#31)
- Kimi K2 (Jul 2025): 32.4 (#64)

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| METR Time Horizons | 62% | 59.2% |
| Terminal-Bench | — | 35.7% |
| Berkeley Function Calling Leaderboard | — | 59.1% |
| TheAgentCompany | 33.1% | — |
| Cybench | 35% | — |
| DeepResearch Bench | 46.6% | — |
| OSWorld | 43.9% | — |

## Reasoning

- Claude Sonnet 4: 22.9 (#187)
- Kimi K2 (Jul 2025): 23.3 (#179)

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| SimpleBench | 45.5% | 26.3% |
| Kagi LLM Benchmark | 73% | 64.4% |
| LMArena Hard Prompts | 1372 | 1384 |
| Epoch Capabilities Index | 141.69 | 146.01 |
| ForecastBench | 60.2 | 60.2 |
| ARC-AGI-2 | 5.9% | — |
| ARC-AGI-1 | 40% | — |
| CritPt | 0.3% | — |
| EnigmaEval | 3.1% | — |
| DTBench | 77.1% | — |
| LMCA | 29% | — |

## Math

- Claude Sonnet 4: 43.3 (#80)
- Kimi K2 (Jul 2025): 42.7 (#83)

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| Omni-MATH | 60.2% | 65.4% |
| LMArena Math | 1375 | 1397 |
| FrontierMath (Feb 2025 set) | 4.1% | 21.4% |
| FrontierMath Tier 4 (v1) | 0% | 0% |
| OTIS Mock AIME 2024-2025 | 71.1% | — |
| MATH Level 5 | 84.4% | — |

## Knowledge

- Claude Sonnet 4: 41.8 (#108)
- Kimi K2 (Jul 2025): 37.3 (#157)

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| MMLU-Pro | 84.3% | 81.9% |
| Confabulations | 13.2% | 20.4% |
| Vectara Hallucination Rate | 10.3% | 17.9% |
| GPQA (HELM) | 70.6% | 65.3% |
| LMArena Expert | 1372 | 1365 |
| GPQA Diamond | 79.2% | — |
| Humanity's Last Exam | 7.8% | — |

## Multimodal

- Claude Sonnet 4: 26.2 (#121)
- Kimi K2 (Jul 2025): —

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Vision | 1191 | — |
| GeoBench | 37% | — |
| VPCT | 34% | — |
| MindCube | 44.8% | — |

## Multilingual

- Claude Sonnet 4: 46.7 (#156)
- Kimi K2 (Jul 2025): 49.6 (#130)

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Non-English | 1333 | 1372 |
| LMArena Chinese | 1350 | 1415 |
| LMArena French | 1363 | 1379 |
| LMArena German | 1331 | 1387 |
| LMArena Japanese | 1302 | 1349 |
| LMArena Korean | 1291 | 1325 |
| LMArena Russian | 1355 | 1385 |
| LMArena Spanish | 1357 | 1386 |

## Instruction Following

- Claude Sonnet 4: 71.7 (#145)
- Kimi K2 (Jul 2025): 71.1 (#156)

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| IFEval | 84% | 85% |
| LMArena Instruction Following | 1376 | 1348 |

## Long Context

- Claude Sonnet 4: 33.7 (#259)
- Kimi K2 (Jul 2025): 41.2 (#145)

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| Fiction.LiveBench | 46.9% | 66.7% |
| LMArena Longer Query | 1398 | 1353 |
| CL-bench | — | 17.6% |

## Writing & Preference

- Claude Sonnet 4: 57.1 (#132)
- Kimi K2 (Jul 2025): 62.3 (#78)

| Benchmark | Claude Sonnet 4 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Text | 1351 | 1380 |
| LMArena Creative Writing | 1345 | 1350 |
| Short-Story Creative Writing | 81.4% | 85.6% |
| EQ-Bench Creative Writing | 1483 | 1666 |
| WildBench | 83.8% | 86.2% |
| LMArena Multi-Turn | 1376 | 1371 |

## FAQ

### Is Claude Sonnet 4 better than Kimi K2 (Jul 2025)?

Claude Sonnet 4 and Kimi K2 (Jul 2025) score almost the same on the Noometry Index (40.8 vs 41.2), so choose on price, context window or the category you care about most.

### Which is cheaper, Claude Sonnet 4 or Kimi K2 (Jul 2025)?

Kimi K2 (Jul 2025) is cheaper. It lists at $0.57 per million input tokens and $2.30 per million output tokens; Claude Sonnet 4 lists at $3 and $15.

### Is Claude Sonnet 4 or Kimi K2 (Jul 2025) better for coding?

Claude Sonnet 4 scores higher on coding benchmarks: 43.5 versus 42.4 in the Noometry coding category.

### Which has the bigger context window?

Kimi K2 (Jul 2025) does, with 262K tokens against 200K.

### How many benchmarks do Claude Sonnet 4 and Kimi K2 (Jul 2025) share?

39 benchmarks have published results for both models. Claude Sonnet 4 has 58 scored results on Noometry and Kimi K2 (Jul 2025) has 42.