# Mistral Medium 3.5 vs o3-pro

> o3-pro is the stronger model overall, scoring 42.7 to 39.6 on the Noometry Index. Mistral Medium 3.5 costs 12× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/mistral-medium-3-5-vs-o3-pro
- Last updated: 2026-10-10
- Shared benchmarks: 2

## Summary

- They share 2 benchmarks with published results for both. Mistral Medium 3.5 scores higher in 2 categories and o3-pro in 3 categories; 5 gaps are clear of the uncertainty.
- The widest gap is in long context, where o3-pro leads 72.1 to 43.2.
- The biggest single-benchmark swing is Kagi LLM Benchmark: 41.4% for Mistral Medium 3.5 and 72.1% for o3-pro.
- Mistral Medium 3.5 is cheaper at $1.50 / $7.50 per million input/output tokens, against $20 / $80 for o3-pro.
- Mistral Medium 3.5 accepts more context: 262K tokens versus 200K.
- Mistral Medium 3.5 has downloadable open weights; the other is API-only.

## Snapshot

| | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| Provider | Mistral AI | OpenAI |
| Noometry Index | 39.6 | 42.7 |
| Rank | 151 | 94 |
| Context | 262K | 200K |
| Input $/M | $1.50 | $20 |
| Output $/M | $7.50 | $80 |
| Weights | Open | Proprietary |

## Coding

- Mistral Medium 3.5: 35.7 (#208)
- o3-pro: 55.1 (#22)

| Benchmark | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| Aider Polyglot | — | 84.9% |
| LMArena WebDev | 1263 | — |
| WeirdML | — | 58.2% |
| LMArena Coding | 1461 | — |

## Reasoning

- Mistral Medium 3.5: 16.6 (#290)
- o3-pro: 24.1 (#152)

| Benchmark | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| Kagi LLM Benchmark | 41.4% | 72.1% |
| Epoch Capabilities Index | 141.42 | 147.43 |
| ARC-AGI-2 | — | 4.9% |
| NYT Connections (extended) | 12.9% | — |
| ARC-AGI-1 | — | 59.3% |
| LMArena Hard Prompts | 1436 | — |
| DTBench | — | 86.9% |
| LMCA | — | 38.5% |

## Math

- Mistral Medium 3.5: 36.4 (#113)
- o3-pro: —

| Benchmark | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| LMArena Math | 1432 | — |

## Knowledge

- Mistral Medium 3.5: 39.3 (#123)
- o3-pro: 29.0 (#234)

| Benchmark | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| Confabulations | — | 14.2% |
| Vectara Hallucination Rate | — | 23.3% |
| LMArena Expert | 1431 | — |

## Multimodal

- Mistral Medium 3.5: 37.6 (#64)
- o3-pro: —

| Benchmark | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| LMArena Vision | 1222 | — |

## Multilingual

- Mistral Medium 3.5: 52.1 (#93)
- o3-pro: —

| Benchmark | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| LMArena Non-English | 1405 | — |
| LMArena Chinese | 1443 | — |
| LMArena French | 1448 | — |
| LMArena German | 1453 | — |
| LMArena Korean | 1387 | — |
| LMArena Russian | 1396 | — |
| LMArena Spanish | 1406 | — |

## Instruction Following

- Mistral Medium 3.5: 74.7 (#87)
- o3-pro: —

| Benchmark | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| LMArena Instruction Following | 1414 | — |

## Long Context

- Mistral Medium 3.5: 43.2 (#101)
- o3-pro: 72.1 (#1)

| Benchmark | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| Fiction.LiveBench | — | 97.2% |
| LMArena Longer Query | 1414 | — |

## Writing & Preference

- Mistral Medium 3.5: 58.6 (#113)
- o3-pro: 57.1 (#128)

| Benchmark | Mistral Medium 3.5 | o3-pro |
|---|---|---|
| LMArena Text | 1421 | — |
| LMArena Creative Writing | 1372 | — |
| Short-Story Creative Writing | — | 84.4% |
| EQ-Bench 4 | 993 | — |
| LMArena Multi-Turn | 1423 | — |

## FAQ

### Is Mistral Medium 3.5 better than o3-pro?

o3-pro is the stronger model overall, scoring 42.7 to 39.6 on the Noometry Index. Mistral Medium 3.5 costs 12× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.

### Which is cheaper, Mistral Medium 3.5 or o3-pro?

Mistral Medium 3.5 is cheaper. It lists at $1.50 per million input tokens and $7.50 per million output tokens; o3-pro lists at $20 and $80.

### Is Mistral Medium 3.5 or o3-pro better for coding?

o3-pro scores higher on coding benchmarks: 55.1 versus 35.7 in the Noometry coding category.

### Which has the bigger context window?

Mistral Medium 3.5 does, with 262K tokens against 200K.

### How many benchmarks do Mistral Medium 3.5 and o3-pro share?

2 benchmarks have published results for both models. Mistral Medium 3.5 has 22 scored results on Noometry and o3-pro has 12.