Noometry

Model comparison

Claude Sonnet 5.5 vs Longcat Flash Chat

Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 42.1 on the Noometry Index.

Last verified . 13 shared benchmarks.

Claude Sonnet 5.5 Anthropic

61.9

Rank #10 Confirmed

Longcat Flash Chat Meituan

42.1

Rank #120 Confirmed

Summary

  • They share 13 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 8 categories and Longcat Flash Chat in 0 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Sonnet 5.5 leads 87.9 to 39.4.
  • The biggest single-benchmark swing is NYT Connections (extended): 80.5% for Claude Sonnet 5.5 and 17.7% for Longcat Flash Chat.
  • Longcat Flash Chat has downloadable open weights; the other is API-only.

Side by side

Claude Sonnet 5.5Longcat Flash Chat
ProviderAnthropicMeituan
Noometry Index61.942.1
Released2026-09-28—
WeightsProprietaryOpen
Context window1M—
Max output128K—
Input $ / M tokens$2—
Output $ / M tokens$10—
Results tracked3219

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Category by category

Coding Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 67.3 (#6), Longcat Flash Chat: 43.5 (#87)

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
LMArena Coding15131471
FrontierCode52.1%—
CursorBench55.5%—
LMArena WebDev1774—
FrontierSWE61.9%—
SciCode61%—
ALE-Bench1,819—

Agentic & Tool Use Not comparable

Claude Sonnet 5.5: 45.0 (#16), Longcat Flash Chat: —

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
APEX-Agents75.5%—

Reasoning Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 54.0 (#28), Longcat Flash Chat: 19.0 (#272)

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
NYT Connections (extended)80.5%17.7%
LMArena Hard Prompts14951440
Kagi LLM Benchmark—43.9%
CritPt31.4%—
Mystery Game Puzzles65%—
Epoch Capabilities Index165.03—

Math Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 87.9 (#6), Longcat Flash Chat: 39.4 (#107)

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
LMArena Math15101442
FrontierMath (Tiers 1-3)88.8%—
FrontierMath Tier 480.5%—
OTIS Mock AIME 2024-2025100%—
ProofBench100%—
FrontierMath Erdős2.9%—

Knowledge Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 66.0 (#12), Longcat Flash Chat: 40.6 (#116)

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
LMArena Expert15401454
GPQA Diamond95.6%—
SimpleQA Verified46.5%—

Multimodal Not comparable

Claude Sonnet 5.5: 51.5 (#6), Longcat Flash Chat: —

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
LMArena Vision1289—
Furniture Assembly75%—

Multilingual Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 55.3 (#30), Longcat Flash Chat: 51.9 (#101)

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
LMArena Non-English14521404
LMArena Chinese15221465
LMArena Russian14511395
LMArena French—1456
LMArena German—1408
LMArena Japanese—1373
LMArena Korean—1371
LMArena Spanish—1445

Instruction Following Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 78.3 (#11), Longcat Flash Chat: 74.4 (#96)

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
LMArena Instruction Following14951411

Long Context Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 45.9 (#28), Longcat Flash Chat: 43.5 (#93)

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
LMArena Longer Query14981425

Writing & Preference Claude Sonnet 5.5 leads

Claude Sonnet 5.5: 66.0 (#40), Longcat Flash Chat: 61.0 (#91)

BenchmarkClaude Sonnet 5.5Longcat Flash Chat
LMArena Text14711427
LMArena Creative Writing14651388
LMArena Multi-Turn14741418

Frequently asked questions

Is Claude Sonnet 5.5 better than Longcat Flash Chat?

Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 42.1 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: 67.3 versus 43.5 in the Noometry coding category.

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

13 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and Longcat Flash Chat has 19.

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