# Claude Sonnet 4.5 vs Mistral Small 3.1

> Claude Sonnet 4.5 is the stronger model overall, scoring 44.1 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 15× less per token, which makes it the better buy when Claude Sonnet 4.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-sonnet-4-5-vs-mistral-small-3-1
- Last updated: 2026-10-12
- Shared benchmarks: 27

## Summary

- They share 27 benchmarks with published results for both. Claude Sonnet 4.5 scores higher in 9 categories and Mistral Small 3.1 in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Claude Sonnet 4.5 leads 66.5 to 37.0.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 77.8% for Claude Sonnet 4.5 and 3.9% for Mistral Small 3.1.
- Mistral Small 3.1 is cheaper at $0.35 / $0.56 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.5.
- Claude Sonnet 4.5 accepts more context: 200K tokens versus 128K.
- Mistral Small 3.1 has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| Provider | Anthropic | Mistral AI |
| Noometry Index | 44.1 | 31.7 |
| Rank | 81 | 269 |
| Context | 200K | 128K |
| Input $/M | $3 | $0.35 |
| Output $/M | $15 | $0.56 |
| Weights | Proprietary | Open |

## Coding

- Claude Sonnet 4.5: 47.3 (#61)
- Mistral Small 3.1: 38.3 (#179)

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Coding | 1489 | 1309 |
| SWE-bench Verified | 71.3% | — |
| SWE-bench Verified (bash only) | 71.4% | — |
| LMArena WebDev | 1393 | — |
| SWE-bench Multilingual | 67% | — |
| SciCode | 44.7% | — |
| GSO | 14.7% | — |
| WeirdML | 47.7% | — |
| ALE-Bench | 796.15 | — |
| AlgoTune | 1.52 | — |

## Agentic & Tool Use

- Claude Sonnet 4.5: 38.3 (#32)
- Mistral Small 3.1: —

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| Terminal-Bench | 46.5% | — |
| Berkeley Function Calling Leaderboard | 73.2% | — |
| GDPval | 42.5% | — |
| Remote Labor Index | 2.1% | — |
| τ²-bench Airline | 72% | — |
| τ²-bench Banking | 25.3% | — |
| τ²-bench Retail | 72.4% | — |
| τ²-bench Telecom | 84.9% | — |
| Cybench | 60% | — |
| DeepResearch Bench | 52.6% | — |
| OSWorld | 62.9% | — |
| LMArena Search | 1159 | — |
| METR Time Horizons | 67.4% | — |
| Vending-Bench 2 | 3,839 | — |

## Reasoning

- Claude Sonnet 4.5: 26.9 (#125)
- Mistral Small 3.1: 19.7 (#254)

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| Chess Puzzles | 12% | 1% |
| LMArena Hard Prompts | 1462 | 1278 |
| Epoch Capabilities Index | 146.84 | 127.48 |
| ARC-AGI-2 | 13.6% | — |
| SimpleBench | 54.3% | — |
| Kagi LLM Benchmark | 57.9% | — |
| NYT Connections (extended) | 37.3% | — |
| ARC-AGI-1 | 63.7% | — |
| CritPt | 1.1% | — |
| EnigmaEval | 6% | — |
| EBR-Bench | 2.4% | — |
| Mystery Game Puzzles | 17% | — |
| DTBench | 83.2% | — |
| LMCA | 38.8% | — |
| ForecastBench | 61.9 | — |

## Math

- Claude Sonnet 4.5: 32.3 (#216)
- Mistral Small 3.1: 14.7 (#301)

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 77.8% | 3.9% |
| Omni-MATH | 55.3% | 24.8% |
| LMArena Math | 1449 | 1262 |
| FrontierMath (Tiers 1-3) | 23.9% | — |
| FrontierMath Tier 4 | 2.4% | — |
| ProofBench | 19% | — |
| MATH Level 5 | 97.7% | — |
| FrontierMath (Feb 2025 set) | 15.2% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |

## Knowledge

- Claude Sonnet 4.5: 48.4 (#76)
- Mistral Small 3.1: 22.6 (#271)

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| GPQA Diamond | 82.3% | 41.9% |
| MMLU-Pro | 86.9% | 61% |
| GPQA (HELM) | 68.6% | 39.2% |
| LMArena Expert | 1482 | 1257 |
| Humanity's Last Exam | 13.7% | — |
| SimpleQA Verified | 30.7% | — |
| Vectara Hallucination Rate | 12% | — |

## Multimodal

- Claude Sonnet 4.5: 34.8 (#89)
- Mistral Small 3.1: 33.2 (#99)

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Vision | — | 1136 |
| VPCT | 39.8% | — |
| LMArena Document | 1450 | — |

## Multilingual

- Claude Sonnet 4.5: 53.4 (#69)
- Mistral Small 3.1: 41.2 (#209)

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Non-English | 1425 | 1255 |
| LMArena Chinese | 1459 | 1253 |
| LMArena French | 1458 | 1273 |
| LMArena German | 1427 | 1266 |
| LMArena Japanese | 1390 | 1208 |
| LMArena Korean | 1403 | 1206 |
| LMArena Russian | 1437 | 1263 |
| LMArena Spanish | 1457 | 1283 |

## Instruction Following

- Claude Sonnet 4.5: 75.0 (#78)
- Mistral Small 3.1: 63.6 (#230)

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| IFEval | 85% | 75% |
| LMArena Instruction Following | 1459 | 1264 |

## Long Context

- Claude Sonnet 4.5: 45.2 (#46)
- Mistral Small 3.1: 39.5 (#178)

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Longer Query | 1476 | 1299 |

## Writing & Preference

- Claude Sonnet 4.5: 66.5 (#34)
- Mistral Small 3.1: 37.0 (#259)

| Benchmark | Claude Sonnet 4.5 | Mistral Small 3.1 |
|---|---|---|
| LMArena Text | 1439 | 1277 |
| LMArena Creative Writing | 1442 | 1253 |
| EQ-Bench Creative Writing | 1678 | 761 |
| WildBench | 85.4% | 78.8% |
| LMArena Multi-Turn | 1465 | 1270 |

## FAQ

### Is Claude Sonnet 4.5 better than Mistral Small 3.1?

Claude Sonnet 4.5 is the stronger model overall, scoring 44.1 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 15× less per token, which makes it the better buy when Claude Sonnet 4.5's lead doesn't matter for your workload.

### Which is cheaper, Claude Sonnet 4.5 or Mistral Small 3.1?

Mistral Small 3.1 is cheaper. It lists at $0.35 per million input tokens and $0.56 per million output tokens; Claude Sonnet 4.5 lists at $3 and $15.

### Is Claude Sonnet 4.5 or Mistral Small 3.1 better for coding?

Claude Sonnet 4.5 scores higher on coding benchmarks: 47.3 versus 38.3 in the Noometry coding category.

### Which has the bigger context window?

Claude Sonnet 4.5 does, with 200K tokens against 128K.

### How many benchmarks do Claude Sonnet 4.5 and Mistral Small 3.1 share?

27 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and Mistral Small 3.1 has 28.