# GPT-5 Nano vs Longcat Flash Chat

> Longcat Flash Chat is the stronger model overall, scoring 41.5 to 33.4 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-nano-vs-longcat-flash-chat
- Last updated: 2026-10-10
- Shared benchmarks: 16

## Summary

- They share 16 benchmarks with published results for both. GPT-5 Nano scores higher in 1 category and Longcat Flash Chat in 7 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Longcat Flash Chat leads 61.2 to 39.4.
- The biggest single-benchmark swing is Kagi LLM Benchmark: 62.2% for GPT-5 Nano and 43.9% for Longcat Flash Chat.
- Longcat Flash Chat has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| Provider | OpenAI | Meituan |
| Noometry Index | 33.4 | 41.5 |
| Rank | 234 | 121 |
| Context | 400K | — |
| Input $/M | $0.05 | — |
| Output $/M | $0.40 | — |
| Weights | Proprietary | Open |

## Coding

- GPT-5 Nano: 33.3 (#248)
- Longcat Flash Chat: 42.9 (#85)

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| LMArena Coding | 1351 | 1471 |
| SWE-bench Verified (bash only) | 34.8% | — |
| WeirdML | 38.1% | — |
| ALE-Bench | 718.67 | — |

## Agentic & Tool Use

- GPT-5 Nano: 25.6 (#99)
- Longcat Flash Chat: —

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| Terminal-Bench | 21.8% | — |
| Berkeley Function Calling Leaderboard | 51.5% | — |

## Reasoning

- GPT-5 Nano: 16.4 (#291)
- Longcat Flash Chat: 18.3 (#267)

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| Kagi LLM Benchmark | 62.2% | 43.9% |
| LMArena Hard Prompts | 1329 | 1440 |
| ARC-AGI-2 | 2.6% | — |
| NYT Connections (extended) | — | 17.7% |
| ARC-AGI-1 | 20.7% | — |
| Chess Puzzles | 27% | — |
| Mystery Game Puzzles | 9% | — |
| DTBench | 62.7% | — |
| LMCA | 7.9% | — |
| Epoch Capabilities Index | 139.39 | — |
| ForecastBench | 59.1 | — |

## Math

- GPT-5 Nano: 29.1 (#221)
- Longcat Flash Chat: 36.6 (#107)

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| LMArena Math | 1318 | 1441 |
| FrontierMath (Tiers 1-3) | 20% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 81.1% | — |
| ProofBench | 12% | — |
| Omni-MATH | 54.6% | — |
| MATH Level 5 | 95.2% | — |
| FrontierMath (Feb 2025 set) | 8.3% | — |
| FrontierMath Tier 4 (v1) | 2.1% | — |

## Knowledge

- GPT-5 Nano: 35.8 (#166)
- Longcat Flash Chat: 40.0 (#111)

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| LMArena Expert | 1321 | 1454 |
| GPQA Diamond | 69.4% | — |
| SimpleQA Verified | 11.7% | — |
| MMLU-Pro | 77.8% | — |
| Vectara Hallucination Rate | 10.5% | — |
| GPQA (HELM) | 67.9% | — |

## Multimodal

- GPT-5 Nano: 30.7 (#102)
- Longcat Flash Chat: —

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| LMArena Vision | 1159 | — |
| VPCT | 37.2% | — |

## Multilingual

- GPT-5 Nano: 45.5 (#167)
- Longcat Flash Chat: 52.1 (#95)

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| LMArena Non-English | 1313 | 1404 |
| LMArena Chinese | 1355 | 1465 |
| LMArena German | 1329 | 1409 |
| LMArena Korean | 1269 | 1372 |
| LMArena Russian | 1296 | 1396 |
| LMArena Spanish | 1360 | 1445 |
| LMArena French | — | 1457 |
| LMArena Japanese | — | 1373 |

## Instruction Following

- GPT-5 Nano: 75.2 (#72)
- Longcat Flash Chat: 74.6 (#92)

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| LMArena Instruction Following | 1306 | 1411 |
| IFEval | 93.2% | — |

## Long Context

- GPT-5 Nano: 31.3 (#275)
- Longcat Flash Chat: 43.5 (#89)

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| LMArena Longer Query | 1313 | 1425 |
| Fiction.LiveBench | 44.4% | — |

## Writing & Preference

- GPT-5 Nano: 39.4 (#244)
- Longcat Flash Chat: 61.2 (#88)

| Benchmark | GPT-5 Nano | Longcat Flash Chat |
|---|---|---|
| LMArena Text | 1320 | 1427 |
| LMArena Creative Writing | 1250 | 1388 |
| LMArena Multi-Turn | 1311 | 1418 |
| EQ-Bench Creative Writing | 705 | — |
| WildBench | 80.6% | — |

## FAQ

### Is GPT-5 Nano better than Longcat Flash Chat?

Longcat Flash Chat is the stronger model overall, scoring 41.5 to 33.4 on the Noometry Index.

### Is GPT-5 Nano or Longcat Flash Chat better for coding?

Longcat Flash Chat scores higher on coding benchmarks: 42.9 versus 33.3 in the Noometry coding category.

### How many benchmarks do GPT-5 Nano and Longcat Flash Chat share?

16 benchmarks have published results for both models. GPT-5 Nano has 48 scored results on Noometry and Longcat Flash Chat has 19.