Model comparison
Longcat Flash Chat vs Mercury 2.5
Longcat Flash Chat is the stronger model overall, scoring 42.1 to 33.5 on the Noometry Index.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in math, where Longcat Flash Chat leads 39.4 to 23.3.
- Longcat Flash Chat has downloadable open weights; the other is API-only.
Side by side
| Longcat Flash Chat | Mercury 2.5 | |
|---|---|---|
| Provider | Meituan | Inception |
| Noometry Index | 42.1 | 33.5 |
| Released | — | 2026-09-08 |
| Weights | Open | Proprietary |
| Context window | — | 260K |
| Max output | — | 66K |
| Input $ / M tokens | — | $0.04 |
| Output $ / M tokens | — | $0.15 |
| Results tracked | 19 | 4 |
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Category by category
Coding Longcat Flash Chat leads
Longcat Flash Chat: 43.5 (#87), Mercury 2.5: 39.5 (#156)
| Benchmark | Longcat Flash Chat | Mercury 2.5 |
|---|---|---|
| SciCode | — | 38.5% |
| LMArena Coding | 1471 | — |
| ALE-Bench | — | 301.65 |
Reasoning Mercury 2.5 leads
Longcat Flash Chat: 19.0 (#272), Mercury 2.5: 22.4 (#193)
| Benchmark | Longcat Flash Chat | Mercury 2.5 |
|---|---|---|
| Kagi LLM Benchmark | 43.9% | — |
| NYT Connections (extended) | 17.7% | — |
| CritPt | — | 0% |
| LMArena Hard Prompts | 1440 | — |
Math Longcat Flash Chat leads
Longcat Flash Chat: 39.4 (#107), Mercury 2.5: 23.3 (#272)
| Benchmark | Longcat Flash Chat | Mercury 2.5 |
|---|---|---|
| ProofBench | — | 3% |
| LMArena Math | 1442 | — |
Knowledge Not comparable
Longcat Flash Chat: 40.6 (#116), Mercury 2.5: —
| Benchmark | Longcat Flash Chat | Mercury 2.5 |
|---|---|---|
| LMArena Expert | 1454 | — |
Multilingual Not comparable
Longcat Flash Chat: 51.9 (#101), Mercury 2.5: —
| Benchmark | Longcat Flash Chat | Mercury 2.5 |
|---|---|---|
| LMArena Non-English | 1404 | — |
| LMArena Chinese | 1465 | — |
| LMArena French | 1456 | — |
| LMArena German | 1408 | — |
| LMArena Japanese | 1373 | — |
| LMArena Korean | 1371 | — |
| LMArena Russian | 1395 | — |
| LMArena Spanish | 1445 | — |
Instruction Following Not comparable
Longcat Flash Chat: 74.4 (#96), Mercury 2.5: —
| Benchmark | Longcat Flash Chat | Mercury 2.5 |
|---|---|---|
| LMArena Instruction Following | 1411 | — |
Long Context Not comparable
Longcat Flash Chat: 43.5 (#93), Mercury 2.5: —
| Benchmark | Longcat Flash Chat | Mercury 2.5 |
|---|---|---|
| LMArena Longer Query | 1425 | — |
Writing & Preference Not comparable
Longcat Flash Chat: 61.0 (#91), Mercury 2.5: —
| Benchmark | Longcat Flash Chat | Mercury 2.5 |
|---|---|---|
| LMArena Text | 1427 | — |
| LMArena Creative Writing | 1388 | — |
| LMArena Multi-Turn | 1418 | — |
Frequently asked questions
Is Longcat Flash Chat better than Mercury 2.5?
Longcat Flash Chat is the stronger model overall, scoring 42.1 to 33.5 on the Noometry Index.
Is Longcat Flash Chat or Mercury 2.5 better for coding?
Longcat Flash Chat scores higher on coding benchmarks: 43.5 versus 39.5 in the Noometry coding category.
How many benchmarks do Longcat Flash Chat and Mercury 2.5 share?
0 benchmarks have published results for both models. Longcat Flash Chat has 19 scored results on Noometry and Mercury 2.5 has 4.