# Mercury vs Step 3.5 Flash

> Step 3.5 Flash is the stronger model overall, scoring 42.3 to 37.6 on the Noometry Index.

- Canonical page: https://noometry.com/compare/mercury-vs-step-3-5-flash
- Last updated: 2026-10-11
- Shared benchmarks: 8

## Summary

- They share 8 benchmarks with published results for both. Mercury scores higher in 0 categories and Step 3.5 Flash in 6 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Step 3.5 Flash leads 58.8 to 46.2.
- Step 3.5 Flash has downloadable open weights; the other is API-only.

## Snapshot

| | Mercury | Step 3.5 Flash |
|---|---|---|
| Provider | Inception | StepFun |
| Noometry Index | 37.6 | 42.3 |
| Rank | 199 | 116 |
| Context | — | 256K |
| Input $/M | — | $0.10 |
| Output $/M | — | $0.30 |
| Weights | Proprietary | Open |

## Coding

- Mercury: 38.7 (#170)
- Step 3.5 Flash: 42.4 (#105)

| Benchmark | Mercury | Step 3.5 Flash |
|---|---|---|
| LMArena Coding | 1322 | 1436 |

## Reasoning

- Mercury: 17.5 (#293)
- Step 3.5 Flash: 22.2 (#202)

| Benchmark | Mercury | Step 3.5 Flash |
|---|---|---|
| LMArena Hard Prompts | 1285 | 1411 |
| Kagi LLM Benchmark | 21.6% | — |
| NYT Connections (extended) | — | 28.4% |

## Math

- Mercury: —
- Step 3.5 Flash: 42.6 (#84)

| Benchmark | Mercury | Step 3.5 Flash |
|---|---|---|
| MathArena Final-Answer Competitions | — | 66.8% |
| LMArena Math | — | 1408 |

## Knowledge

- Mercury: —
- Step 3.5 Flash: 39.6 (#132)

| Benchmark | Mercury | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | — | 1421 |

## Multilingual

- Mercury: 41.6 (#206)
- Step 3.5 Flash: 50.5 (#119)

| Benchmark | Mercury | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1260 | 1385 |
| LMArena Chinese | — | 1447 |
| LMArena French | — | 1421 |
| LMArena German | — | 1405 |
| LMArena Japanese | — | 1354 |
| LMArena Korean | — | 1352 |
| LMArena Russian | — | 1385 |
| LMArena Spanish | — | 1419 |

## Instruction Following

- Mercury: 65.2 (#224)
- Step 3.5 Flash: 73.1 (#124)

| Benchmark | Mercury | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1239 | 1385 |

## Long Context

- Mercury: 38.4 (#198)
- Step 3.5 Flash: 42.8 (#117)

| Benchmark | Mercury | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1266 | 1402 |

## Writing & Preference

- Mercury: 46.2 (#221)
- Step 3.5 Flash: 58.8 (#113)

| Benchmark | Mercury | Step 3.5 Flash |
|---|---|---|
| LMArena Text | 1282 | 1403 |
| LMArena Creative Writing | 1191 | 1357 |
| LMArena Multi-Turn | 1282 | 1405 |

## FAQ

### Is Mercury better than Step 3.5 Flash?

Step 3.5 Flash is the stronger model overall, scoring 42.3 to 37.6 on the Noometry Index.

### Is Mercury or Step 3.5 Flash better for coding?

Step 3.5 Flash scores higher on coding benchmarks: 42.4 versus 38.7 in the Noometry coding category.

### How many benchmarks do Mercury and Step 3.5 Flash share?

8 benchmarks have published results for both models. Mercury has 9 scored results on Noometry and Step 3.5 Flash has 19.