# Claude Sonnet 5 vs Kimi K2 (Jul 2025)

> Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 41.2 on the Noometry Index. Kimi K2 (Jul 2025) costs 4.0× less per token, which makes it the better buy when Claude Sonnet 5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-sonnet-5-vs-kimi-k2
- Last updated: 2026-10-10
- Shared benchmarks: 24

## Summary

- They share 24 benchmarks with published results for both. Claude Sonnet 5 scores higher in 9 categories and Kimi K2 (Jul 2025) in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Sonnet 5 leads 49.1 to 23.3.
- The biggest single-benchmark swing is SimpleBench: 60.6% for Claude Sonnet 5 and 26.3% for Kimi K2 (Jul 2025).
- Kimi K2 (Jul 2025) is cheaper at $0.57 / $2.30 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.
- Claude Sonnet 5 accepts more context: 1M tokens versus 262K.
- Kimi K2 (Jul 2025) has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| Provider | Anthropic | Moonshot AI |
| Noometry Index | 54.6 | 41.2 |
| Rank | 29 | 140 |
| Context | 1M | 262K |
| Input $/M | $2 | $0.57 |
| Output $/M | $10 | $2.30 |
| Weights | Proprietary | Open |

## Coding

- Claude Sonnet 5: 55.5 (#26)
- Kimi K2 (Jul 2025): 42.4 (#102)

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| GSO | 37.3% | 4.9% |
| WeirdML | 68.8% | 42.8% |
| LMArena Coding | 1483 | 1399 |
| ALE-Bench | 1,463 | 597.5 |
| DeepSWE | 53.8% | — |
| FrontierCode | 42.7% | — |
| SWE-bench Verified (bash only) | — | 63.4% |
| Aider Polyglot | — | 59.1% |
| CursorBench | 34.1% | — |
| LMArena WebDev | 1541 | — |
| SciCode | 54.3% | — |

## Agentic & Tool Use

- Claude Sonnet 5: 42.8 (#18)
- Kimi K2 (Jul 2025): 32.4 (#64)

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| Terminal-Bench | — | 35.7% |
| APEX-Agents | 54.5% | — |
| Berkeley Function Calling Leaderboard | — | 59.1% |
| GBAEval | 65.3% | — |
| LMArena Search | 1194 | — |
| METR Time Horizons | — | 59.2% |
| Vending-Bench 2 | 6,378 | — |

## Reasoning

- Claude Sonnet 5: 49.1 (#39)
- Kimi K2 (Jul 2025): 23.3 (#179)

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| SimpleBench | 60.6% | 26.3% |
| LMArena Hard Prompts | 1461 | 1384 |
| Epoch Capabilities Index | 156.21 | 146.01 |
| ForecastBench | 61.1 | 60.2 |
| Kagi LLM Benchmark | — | 64.4% |
| NYT Connections (extended) | 75.1% | — |
| CritPt | 16.9% | — |
| Chess Puzzles | 35% | — |
| Mystery Game Puzzles | 35% | — |
| DTBench | 92.5% | — |
| LMCA | 50% | — |
| Surface Evolver Bench | 60% | — |
| Bench to the Future 3 | 0.14 | — |

## Math

- Claude Sonnet 5: 66.2 (#27)
- Kimi K2 (Jul 2025): 42.7 (#83)

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Math | 1467 | 1397 |
| FrontierMath (Tiers 1-3) | 65.6% | — |
| FrontierMath Tier 4 | 29.3% | — |
| OTIS Mock AIME 2024-2025 | 94.7% | — |
| ProofBench | 77% | — |
| Omni-MATH | — | 65.4% |
| FrontierMath (Feb 2025 set) | — | 21.4% |
| FrontierMath Tier 4 (v1) | — | 0% |

## Knowledge

- Claude Sonnet 5: 55.6 (#47)
- Kimi K2 (Jul 2025): 37.3 (#157)

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Expert | 1490 | 1365 |
| GPQA Diamond | 90.5% | — |
| SimpleQA Verified | 33.7% | — |
| MMLU-Pro | — | 81.9% |
| Confabulations | — | 20.4% |
| Vectara Hallucination Rate | — | 17.9% |
| GPQA (HELM) | — | 65.3% |

## Multimodal

- Claude Sonnet 5: 42.4 (#31)
- Kimi K2 (Jul 2025): —

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Vision | 1274 | — |
| Blueprint-Bench 2 | 24.9% | — |
| LMArena Document | 1466 | — |

## Multilingual

- Claude Sonnet 5: 53.8 (#55)
- Kimi K2 (Jul 2025): 49.6 (#130)

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Non-English | 1431 | 1372 |
| LMArena Chinese | 1477 | 1415 |
| LMArena French | 1460 | 1379 |
| LMArena German | 1440 | 1387 |
| LMArena Japanese | 1422 | 1349 |
| LMArena Korean | 1411 | 1325 |
| LMArena Russian | 1451 | 1385 |
| LMArena Spanish | 1437 | 1386 |

## Instruction Following

- Claude Sonnet 5: 76.3 (#41)
- Kimi K2 (Jul 2025): 71.1 (#156)

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Instruction Following | 1452 | 1348 |
| IFEval | — | 85% |

## Long Context

- Claude Sonnet 5: 44.8 (#55)
- Kimi K2 (Jul 2025): 41.2 (#145)

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Longer Query | 1463 | 1353 |
| Fiction.LiveBench | — | 66.7% |
| CL-bench | — | 17.6% |

## Writing & Preference

- Claude Sonnet 5: 69.2 (#25)
- Kimi K2 (Jul 2025): 62.3 (#78)

| Benchmark | Claude Sonnet 5 | Kimi K2 (Jul 2025) |
|---|---|---|
| LMArena Text | 1442 | 1380 |
| LMArena Creative Writing | 1416 | 1350 |
| EQ-Bench Creative Writing | 1794 | 1666 |
| LMArena Multi-Turn | 1454 | 1371 |
| Short-Story Creative Writing | — | 85.6% |
| WildBench | — | 86.2% |
| EQ-Bench 4 | 1236 | — |

## FAQ

### Is Claude Sonnet 5 better than Kimi K2 (Jul 2025)?

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 41.2 on the Noometry Index. Kimi K2 (Jul 2025) costs 4.0× less per token, which makes it the better buy when Claude Sonnet 5's lead doesn't matter for your workload.

### Which is cheaper, Claude Sonnet 5 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 5 lists at $2 and $10.

### Is Claude Sonnet 5 or Kimi K2 (Jul 2025) better for coding?

Claude Sonnet 5 scores higher on coding benchmarks: 55.5 versus 42.4 in the Noometry coding category.

### Which has the bigger context window?

Claude Sonnet 5 does, with 1M tokens against 262K.

### How many benchmarks do Claude Sonnet 5 and Kimi K2 (Jul 2025) share?

24 benchmarks have published results for both models. Claude Sonnet 5 has 51 scored results on Noometry and Kimi K2 (Jul 2025) has 42.