# Claude Sonnet 5.5 vs Longcat Flash Chat

> Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 41.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-sonnet-5-5-vs-longcat-flash-chat
- Last updated: 2026-10-10
- Shared benchmarks: 0

## Summary

- The widest gap is in math, where Claude Sonnet 5.5 leads 88.7 to 36.6.
- Longcat Flash Chat has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| Provider | Anthropic | Meituan |
| Noometry Index | 60.5 | 41.5 |
| Rank | 10 | 121 |
| Context | 1M | — |
| Input $/M | $2 | — |
| Output $/M | $10 | — |
| Weights | Proprietary | Open |

## Coding

- Claude Sonnet 5.5: 65.5 (#6)
- Longcat Flash Chat: 42.9 (#85)

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| FrontierCode | 52.1% | — |
| CursorBench | 55.5% | — |
| LMArena WebDev | 1699 | — |
| FrontierSWE | 61.9% | — |
| SciCode | 61% | — |
| LMArena Coding | — | 1471 |
| ALE-Bench | 1,819 | — |

## Agentic & Tool Use

- Claude Sonnet 5.5: 44.9 (#14)
- Longcat Flash Chat: —

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| APEX-Agents | 75.5% | — |

## Reasoning

- Claude Sonnet 5.5: 52.4 (#29)
- Longcat Flash Chat: 18.3 (#267)

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| Kagi LLM Benchmark | — | 43.9% |
| NYT Connections (extended) | — | 17.7% |
| CritPt | 31.4% | — |
| LMArena Hard Prompts | — | 1440 |
| Mystery Game Puzzles | 65% | — |

## Math

- Claude Sonnet 5.5: 88.7 (#4)
- Longcat Flash Chat: 36.6 (#107)

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| FrontierMath (Tiers 1-3) | 88.8% | — |
| FrontierMath Tier 4 | 80.5% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 100% | — |
| LMArena Math | — | 1441 |

## Knowledge

- Claude Sonnet 5.5: 66.0 (#11)
- Longcat Flash Chat: 40.0 (#111)

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| GPQA Diamond | 95.6% | — |
| SimpleQA Verified | 46.5% | — |
| LMArena Expert | — | 1454 |

## Multimodal

- Claude Sonnet 5.5: 53.2 (#5)
- Longcat Flash Chat: —

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| Furniture Assembly | 75% | — |

## Multilingual

- Claude Sonnet 5.5: —
- Longcat Flash Chat: 52.1 (#95)

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Non-English | — | 1404 |
| LMArena Chinese | — | 1465 |
| LMArena French | — | 1457 |
| LMArena German | — | 1409 |
| LMArena Japanese | — | 1373 |
| LMArena Korean | — | 1372 |
| LMArena Russian | — | 1396 |
| LMArena Spanish | — | 1445 |

## Instruction Following

- Claude Sonnet 5.5: —
- Longcat Flash Chat: 74.6 (#92)

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Instruction Following | — | 1411 |

## Long Context

- Claude Sonnet 5.5: —
- Longcat Flash Chat: 43.5 (#89)

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Longer Query | — | 1425 |

## Writing & Preference

- Claude Sonnet 5.5: —
- Longcat Flash Chat: 61.2 (#88)

| Benchmark | Claude Sonnet 5.5 | Longcat Flash Chat |
|---|---|---|
| LMArena Text | — | 1427 |
| LMArena Creative Writing | — | 1388 |
| LMArena Multi-Turn | — | 1418 |

## FAQ

### Is Claude Sonnet 5.5 better than Longcat Flash Chat?

Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 41.5 on the Noometry Index.

### Is Claude Sonnet 5.5 or Longcat Flash Chat better for coding?

Claude Sonnet 5.5 scores higher on coding benchmarks: 65.5 versus 42.9 in the Noometry coding category.

### How many benchmarks do Claude Sonnet 5.5 and Longcat Flash Chat share?

0 benchmarks have published results for both models. Claude Sonnet 5.5 has 16 scored results on Noometry and Longcat Flash Chat has 19.