# Mistral Small 3.1 vs Step 3.5 Flash

> Step 3.5 Flash is the stronger model overall, scoring 42.3 to 31.7 on the Noometry Index.

- Canonical page: https://noometry.com/compare/mistral-small-3-1-vs-step-3-5-flash
- Last updated: 2026-10-10
- Shared benchmarks: 17

## Summary

- They share 17 benchmarks with published results for both. Mistral Small 3.1 scores higher in 0 categories and Step 3.5 Flash in 8 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where Step 3.5 Flash leads 42.6 to 14.7.
- Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $0.35 / $0.56 for Mistral Small 3.1.
- Step 3.5 Flash accepts more context: 256K tokens versus 128K.

## Snapshot

| | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| Provider | Mistral AI | StepFun |
| Noometry Index | 31.7 | 42.3 |
| Rank | 269 | 116 |
| Context | 128K | 256K |
| Input $/M | $0.35 | $0.10 |
| Output $/M | $0.56 | $0.30 |
| Weights | Open | Open |

## Coding

- Mistral Small 3.1: 38.3 (#179)
- Step 3.5 Flash: 42.4 (#105)

| Benchmark | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Coding | 1309 | 1436 |

## Reasoning

- Mistral Small 3.1: 19.7 (#254)
- Step 3.5 Flash: 22.2 (#202)

| Benchmark | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Hard Prompts | 1278 | 1411 |
| NYT Connections (extended) | — | 28.4% |
| Chess Puzzles | 1% | — |
| Epoch Capabilities Index | 127.48 | — |

## Math

- Mistral Small 3.1: 14.7 (#301)
- Step 3.5 Flash: 42.6 (#84)

| Benchmark | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Math | 1262 | 1408 |
| MathArena Final-Answer Competitions | — | 66.8% |
| OTIS Mock AIME 2024-2025 | 3.9% | — |
| Omni-MATH | 24.8% | — |

## Knowledge

- Mistral Small 3.1: 22.6 (#271)
- Step 3.5 Flash: 39.6 (#132)

| Benchmark | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | 1257 | 1421 |
| GPQA Diamond | 41.9% | — |
| MMLU-Pro | 61% | — |
| GPQA (HELM) | 39.2% | — |

## Multimodal

- Mistral Small 3.1: 33.2 (#99)
- Step 3.5 Flash: —

| Benchmark | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Vision | 1136 | — |

## Multilingual

- Mistral Small 3.1: 41.2 (#209)
- Step 3.5 Flash: 50.5 (#119)

| Benchmark | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1255 | 1385 |
| LMArena Chinese | 1253 | 1447 |
| LMArena French | 1273 | 1421 |
| LMArena German | 1266 | 1405 |
| LMArena Japanese | 1208 | 1354 |
| LMArena Korean | 1206 | 1352 |
| LMArena Russian | 1263 | 1385 |
| LMArena Spanish | 1283 | 1419 |

## Instruction Following

- Mistral Small 3.1: 63.6 (#230)
- Step 3.5 Flash: 73.1 (#124)

| Benchmark | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1264 | 1385 |
| IFEval | 75% | — |

## Long Context

- Mistral Small 3.1: 39.5 (#178)
- Step 3.5 Flash: 42.8 (#117)

| Benchmark | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1299 | 1402 |

## Writing & Preference

- Mistral Small 3.1: 37.0 (#259)
- Step 3.5 Flash: 58.8 (#113)

| Benchmark | Mistral Small 3.1 | Step 3.5 Flash |
|---|---|---|
| LMArena Text | 1277 | 1403 |
| LMArena Creative Writing | 1253 | 1357 |
| LMArena Multi-Turn | 1270 | 1405 |
| EQ-Bench Creative Writing | 761 | — |
| WildBench | 78.8% | — |

## FAQ

### Is Mistral Small 3.1 better than Step 3.5 Flash?

Step 3.5 Flash is the stronger model overall, scoring 42.3 to 31.7 on the Noometry Index.

### Which is cheaper, Mistral Small 3.1 or Step 3.5 Flash?

Step 3.5 Flash is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; Mistral Small 3.1 lists at $0.35 and $0.56.

### Is Mistral Small 3.1 or Step 3.5 Flash better for coding?

Step 3.5 Flash scores higher on coding benchmarks: 42.4 versus 38.3 in the Noometry coding category.

### Which has the bigger context window?

Step 3.5 Flash does, with 256K tokens against 128K.

### How many benchmarks do Mistral Small 3.1 and Step 3.5 Flash share?

17 benchmarks have published results for both models. Mistral Small 3.1 has 28 scored results on Noometry and Step 3.5 Flash has 19.