# GPT-5.5 Instant vs Longcat Flash Chat

> GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 41.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-5-instant-vs-longcat-flash-chat
- Last updated: 2026-10-10
- Shared benchmarks: 17

## Summary

- They share 17 benchmarks with published results for both. GPT-5.5 Instant scores higher in 5 categories and Longcat Flash Chat in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where Longcat Flash Chat leads 36.6 to 26.1.
- Longcat Flash Chat has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| Provider | OpenAI | Meituan |
| Noometry Index | 42.5 | 41.5 |
| Rank | 99 | 121 |
| Context | — | — |
| Input $/M | — | — |
| Output $/M | — | — |
| Weights | Proprietary | Open |

## Coding

- GPT-5.5 Instant: 43.7 (#73)
- Longcat Flash Chat: 42.9 (#85)

| Benchmark | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| LMArena Coding | 1433 | 1471 |
| SciCode | 48.6% | — |

## Reasoning

- GPT-5.5 Instant: 24.2 (#149)
- Longcat Flash Chat: 18.3 (#267)

| Benchmark | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| LMArena Hard Prompts | 1426 | 1440 |
| Kagi LLM Benchmark | — | 43.9% |
| NYT Connections (extended) | — | 17.7% |
| CritPt | 0% | — |
| Chess Puzzles | 12% | — |
| Epoch Capabilities Index | 142.48 | — |

## Math

- GPT-5.5 Instant: 26.1 (#241)
- Longcat Flash Chat: 36.6 (#107)

| Benchmark | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| LMArena Math | 1420 | 1441 |
| FrontierMath (Tiers 1-3) | 26.3% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 68.1% | — |

## Knowledge

- GPT-5.5 Instant: 48.9 (#68)
- Longcat Flash Chat: 40.0 (#111)

| Benchmark | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| LMArena Expert | 1409 | 1454 |
| GPQA Diamond | 82.5% | — |

## Multimodal

- GPT-5.5 Instant: 39.3 (#48)
- Longcat Flash Chat: —

| Benchmark | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| LMArena Vision | 1250 | — |
| LMArena Document | 1403 | — |

## Multilingual

- GPT-5.5 Instant: 53.0 (#76)
- Longcat Flash Chat: 52.1 (#95)

| Benchmark | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| LMArena Non-English | 1417 | 1404 |
| LMArena Chinese | 1457 | 1465 |
| LMArena French | 1428 | 1457 |
| LMArena German | 1410 | 1409 |
| LMArena Japanese | 1408 | 1373 |
| LMArena Korean | 1393 | 1372 |
| LMArena Russian | 1430 | 1396 |
| LMArena Spanish | 1430 | 1445 |

## Instruction Following

- GPT-5.5 Instant: 74.4 (#94)
- Longcat Flash Chat: 74.6 (#92)

| Benchmark | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| LMArena Instruction Following | 1407 | 1411 |

## Long Context

- GPT-5.5 Instant: 43.4 (#92)
- Longcat Flash Chat: 43.5 (#89)

| Benchmark | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| LMArena Longer Query | 1422 | 1425 |

## Writing & Preference

- GPT-5.5 Instant: 62.0 (#81)
- Longcat Flash Chat: 61.2 (#88)

| Benchmark | GPT-5.5 Instant | Longcat Flash Chat |
|---|---|---|
| LMArena Text | 1419 | 1427 |
| LMArena Creative Writing | 1420 | 1388 |
| LMArena Multi-Turn | 1434 | 1418 |

## FAQ

### Is GPT-5.5 Instant better than Longcat Flash Chat?

GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 41.5 on the Noometry Index.

### Is GPT-5.5 Instant or Longcat Flash Chat better for coding?

They score almost the same on coding (43.7 vs 42.9); test both on your own repository before choosing.

### How many benchmarks do GPT-5.5 Instant and Longcat Flash Chat share?

17 benchmarks have published results for both models. GPT-5.5 Instant has 27 scored results on Noometry and Longcat Flash Chat has 19.