# Claude Sonnet 5.5 vs Mistral Small 3

> Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 30.9 on the Noometry Index. Mistral Small 3 costs 70× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-sonnet-5-5-vs-mistral-small-3
- Last updated: 2026-10-10
- Shared benchmarks: 2

## Summary

- They share 2 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 4 categories and Mistral Small 3 in 0 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 88.7 to 15.3.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 100% for Claude Sonnet 5.5 and 6.7% for Mistral Small 3.
- Mistral Small 3 is cheaper at $0.05 / $0.08 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
- Claude Sonnet 5.5 accepts more context: 1M tokens versus 33K.
- Mistral Small 3 has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| Provider | Anthropic | Mistral AI |
| Noometry Index | 60.5 | 30.9 |
| Rank | 10 | 268 |
| Context | 1M | 33K |
| Input $/M | $2 | $0.05 |
| Output $/M | $10 | $0.08 |
| Weights | Proprietary | Open |

## Coding

- Claude Sonnet 5.5: 65.5 (#6)
- Mistral Small 3: 36.0 (#203)

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| FrontierCode | 52.1% | — |
| CursorBench | 55.5% | — |
| LMArena WebDev | 1699 | — |
| FrontierSWE | 61.9% | — |
| SciCode | 61% | — |
| BigCodeBench Instruct | — | 45.3% |
| LMArena Coding | — | 1246 |
| BigCodeBench Complete | — | 50.4% |
| ALE-Bench | 1,819 | — |

## Agentic & Tool Use

- Claude Sonnet 5.5: 44.9 (#14)
- Mistral Small 3: —

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| APEX-Agents | 75.5% | — |

## Reasoning

- Claude Sonnet 5.5: 52.4 (#29)
- Mistral Small 3: 18.2 (#269)

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| CritPt | 31.4% | — |
| Chess Puzzles | — | 0% |
| LMArena Hard Prompts | — | 1233 |
| Mystery Game Puzzles | 65% | — |
| Epoch Capabilities Index | — | 127.06 |

## Math

- Claude Sonnet 5.5: 88.7 (#4)
- Mistral Small 3: 15.3 (#290)

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 6.7% |
| FrontierMath (Tiers 1-3) | 88.8% | — |
| FrontierMath Tier 4 | 80.5% | — |
| ProofBench | 100% | — |
| LMArena Math | — | 1240 |

## Knowledge

- Claude Sonnet 5.5: 66.0 (#11)
- Mistral Small 3: 25.0 (#258)

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| GPQA Diamond | 95.6% | 47.3% |
| SimpleQA Verified | 46.5% | — |
| Confabulations | — | 25.2% |
| LMArena Expert | — | 1202 |

## Multimodal

- Claude Sonnet 5.5: 53.2 (#5)
- Mistral Small 3: —

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| Furniture Assembly | 75% | — |

## Multilingual

- Claude Sonnet 5.5: —
- Mistral Small 3: 37.5 (#231)

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| LMArena Non-English | — | 1198 |
| LMArena Chinese | — | 1204 |
| LMArena French | — | 1202 |
| LMArena German | — | 1211 |
| LMArena Japanese | — | 1111 |
| LMArena Korean | — | 1188 |
| LMArena Russian | — | 1216 |

## Instruction Following

- Claude Sonnet 5.5: —
- Mistral Small 3: 63.9 (#224)

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| LMArena Instruction Following | — | 1214 |

## Long Context

- Claude Sonnet 5.5: —
- Mistral Small 3: 37.8 (#206)

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| LMArena Longer Query | — | 1246 |

## Writing & Preference

- Claude Sonnet 5.5: —
- Mistral Small 3: 32.4 (#275)

| Benchmark | Claude Sonnet 5.5 | Mistral Small 3 |
|---|---|---|
| LMArena Text | — | 1234 |
| LMArena Creative Writing | — | 1195 |
| EQ-Bench Creative Writing | — | 707 |
| LMArena Multi-Turn | — | 1217 |

## FAQ

### Is Claude Sonnet 5.5 better than Mistral Small 3?

Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 30.9 on the Noometry Index. Mistral Small 3 costs 70× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.

### Which is cheaper, Claude Sonnet 5.5 or Mistral Small 3?

Mistral Small 3 is cheaper. It lists at $0.05 per million input tokens and $0.08 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.

### Is Claude Sonnet 5.5 or Mistral Small 3 better for coding?

Claude Sonnet 5.5 scores higher on coding benchmarks: 65.5 versus 36.0 in the Noometry coding category.

### Which has the bigger context window?

Claude Sonnet 5.5 does, with 1M tokens against 33K.

### How many benchmarks do Claude Sonnet 5.5 and Mistral Small 3 share?

2 benchmarks have published results for both models. Claude Sonnet 5.5 has 16 scored results on Noometry and Mistral Small 3 has 24.