# Claude Sonnet 5.5 vs Kimi K2.6

> Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 47.7 on the Noometry Index. Kimi K2.6 costs 2.3× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-sonnet-5-5-vs-kimi-k2-6
- Last updated: 2026-10-12
- Shared benchmarks: 27

## Summary

- They share 27 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 9 categories and Kimi K2.6 in 1 category; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 87.9 to 57.0.
- The biggest single-benchmark swing is ProofBench: 100% for Claude Sonnet 5.5 and 16% for Kimi K2.6.
- Kimi K2.6 is cheaper at $0.95 / $4 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
- Claude Sonnet 5.5 accepts more context: 1M tokens versus 262K.
- Kimi K2.6 has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| Provider | Anthropic | Moonshot AI |
| Noometry Index | 61.9 | 47.7 |
| Rank | 10 | 60 |
| Context | 1M | 262K |
| Input $/M | $2 | $0.95 |
| Output $/M | $10 | $4 |
| Weights | Proprietary | Open |

## Coding

- Claude Sonnet 5.5: 67.3 (#6)
- Kimi K2.6: 50.7 (#43)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| LMArena WebDev | 1774 | 1509 |
| SciCode | 61% | 53.5% |
| LMArena Coding | 1513 | 1488 |
| ALE-Bench | 1,819 | 1,093 |
| SWE-bench Verified | — | 76.7% |
| FrontierCode | 52.1% | — |
| CursorBench | 55.5% | — |
| FrontierSWE | 61.9% | — |
| WeirdML | — | 55.9% |

## Agentic & Tool Use

- Claude Sonnet 5.5: 45.0 (#16)
- Kimi K2.6: 21.9 (#137)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| APEX-Agents | 75.5% | — |
| OSWorld 2.0 | — | 4.6% |
| ExploitBench | — | 18.4% |
| GBAEval | — | 0.9% |
| GDP.pdf | — | 12% |
| Vending-Bench 2 | — | 6,205 |

## Reasoning

- Claude Sonnet 5.5: 54.0 (#28)
- Kimi K2.6: 40.5 (#55)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| NYT Connections (extended) | 80.5% | 87.2% |
| CritPt | 31.4% | 8% |
| LMArena Hard Prompts | 1495 | 1470 |
| Mystery Game Puzzles | 65% | 18% |
| Epoch Capabilities Index | 165.03 | 151.05 |
| Chess Puzzles | — | 26% |
| EBR-Bench | — | 2.4% |
| DTBench | — | 90.9% |
| LMCA | — | 37.3% |

## Math

- Claude Sonnet 5.5: 87.9 (#6)
- Kimi K2.6: 57.0 (#41)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 88.8% | 57.2% |
| FrontierMath Tier 4 | 80.5% | 25.6% |
| OTIS Mock AIME 2024-2025 | 100% | 96.1% |
| ProofBench | 100% | 16% |
| LMArena Math | 1510 | 1475 |
| MathArena Final-Answer Competitions | — | 72.9% |
| FrontierMath (Feb 2025 set) | — | 39% |
| FrontierMath Erdős | 2.9% | — |
| FrontierMath Tier 4 (v1) | — | 14.6% |

## Knowledge

- Claude Sonnet 5.5: 66.0 (#12)
- Kimi K2.6: 54.0 (#54)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| GPQA Diamond | 95.6% | 90.8% |
| SimpleQA Verified | 46.5% | 34.9% |
| LMArena Expert | 1540 | 1491 |
| Vectara Hallucination Rate | — | 10.8% |

## Multimodal

- Claude Sonnet 5.5: 51.5 (#6)
- Kimi K2.6: 31.6 (#103)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| LMArena Vision | 1289 | 1283 |
| Furniture Assembly | 75% | 21.7% |
| Blueprint-Bench 2 | — | 3.9% |
| LMArena Document | — | 1451 |

## Multilingual

- Claude Sonnet 5.5: 55.3 (#30)
- Kimi K2.6: 54.9 (#37)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| LMArena Non-English | 1452 | 1446 |
| LMArena Chinese | 1522 | 1521 |
| LMArena Russian | 1451 | 1446 |
| LMArena French | — | 1471 |
| LMArena German | — | 1450 |
| LMArena Japanese | — | 1443 |
| LMArena Korean | — | 1427 |
| LMArena Spanish | — | 1464 |

## Instruction Following

- Claude Sonnet 5.5: 78.3 (#11)
- Kimi K2.6: 76.3 (#43)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| LMArena Instruction Following | 1495 | 1451 |

## Long Context

- Claude Sonnet 5.5: 45.9 (#28)
- Kimi K2.6: 44.9 (#52)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| LMArena Longer Query | 1498 | 1468 |

## Writing & Preference

- Claude Sonnet 5.5: 66.0 (#40)
- Kimi K2.6: 68.5 (#26)

| Benchmark | Claude Sonnet 5.5 | Kimi K2.6 |
|---|---|---|
| LMArena Text | 1471 | 1455 |
| LMArena Creative Writing | 1465 | 1434 |
| LMArena Multi-Turn | 1474 | 1453 |
| EQ-Bench Creative Writing | — | 1725 |
| EQ-Bench 4 | — | 1202 |

## FAQ

### Is Claude Sonnet 5.5 better than Kimi K2.6?

Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 47.7 on the Noometry Index. Kimi K2.6 costs 2.3× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.

### Which is cheaper, Claude Sonnet 5.5 or Kimi K2.6?

Kimi K2.6 is cheaper. It lists at $0.95 per million input tokens and $4 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.

### Is Claude Sonnet 5.5 or Kimi K2.6 better for coding?

Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 50.7 in the Noometry coding category.

### Which has the bigger context window?

Claude Sonnet 5.5 does, with 1M tokens against 262K.

### How many benchmarks do Claude Sonnet 5.5 and Kimi K2.6 share?

27 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and Kimi K2.6 has 51.