# GPT-5.5 Pro vs Mistral Medium 3.5

> GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 39.6 on the Noometry Index. Mistral Medium 3.5 costs 23× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-5-5-pro-vs-mistral-medium-3-5
- Last updated: 2026-10-10
- Shared benchmarks: 1

## Summary

- They share 1 benchmark with published results for both. GPT-5.5 Pro scores higher in 3 categories and Mistral Medium 3.5 in 0 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-5.5 Pro leads 73.6 to 16.6.
- Mistral Medium 3.5 is cheaper at $1.50 / $7.50 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
- GPT-5.5 Pro accepts more context: 1.05M tokens versus 262K.
- Mistral Medium 3.5 has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 64.3 | 39.6 |
| Rank | 7 | 151 |
| Context | 1.05M | 262K |
| Input $/M | $30 | $1.50 |
| Output $/M | $180 | $7.50 |
| Weights | Proprietary | Open |

## Coding

- GPT-5.5 Pro: —
- Mistral Medium 3.5: 35.7 (#208)

| Benchmark | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| LMArena WebDev | — | 1263 |
| LMArena Coding | — | 1461 |

## Reasoning

- GPT-5.5 Pro: 73.6 (#7)
- Mistral Medium 3.5: 16.6 (#290)

| Benchmark | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| Epoch Capabilities Index | 162.45 | 141.42 |
| ARC-AGI-2 | 84.6% | — |
| SimpleBench | 76.9% | — |
| Kagi LLM Benchmark | — | 41.4% |
| NYT Connections (extended) | — | 12.9% |
| ARC-AGI-1 | 96.5% | — |
| CritPt | 30.6% | — |
| Chess Puzzles | 64% | — |
| LMArena Hard Prompts | — | 1436 |
| DTBench | 96% | — |
| LMCA | 53.9% | — |

## Math

- GPT-5.5 Pro: 83.8 (#8)
- Mistral Medium 3.5: 36.4 (#113)

| Benchmark | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 87.7% | — |
| FrontierMath Tier 4 | 78% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| LMArena Math | — | 1432 |
| FrontierMath (Feb 2025 set) | 52.4% | — |
| FrontierMath Tier 4 (v1) | 39.6% | — |

## Knowledge

- GPT-5.5 Pro: 64.2 (#17)
- Mistral Medium 3.5: 39.3 (#123)

| Benchmark | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| GPQA Diamond | 93.9% | — |
| LMArena Expert | — | 1431 |

## Multimodal

- GPT-5.5 Pro: —
- Mistral Medium 3.5: 37.6 (#64)

| Benchmark | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| LMArena Vision | — | 1222 |

## Multilingual

- GPT-5.5 Pro: —
- Mistral Medium 3.5: 52.1 (#93)

| Benchmark | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| LMArena Non-English | — | 1405 |
| LMArena Chinese | — | 1443 |
| LMArena French | — | 1448 |
| LMArena German | — | 1453 |
| LMArena Korean | — | 1387 |
| LMArena Russian | — | 1396 |
| LMArena Spanish | — | 1406 |

## Instruction Following

- GPT-5.5 Pro: —
- Mistral Medium 3.5: 74.7 (#87)

| Benchmark | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| LMArena Instruction Following | — | 1414 |

## Long Context

- GPT-5.5 Pro: —
- Mistral Medium 3.5: 43.2 (#101)

| Benchmark | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| LMArena Longer Query | — | 1414 |

## Writing & Preference

- GPT-5.5 Pro: —
- Mistral Medium 3.5: 58.6 (#113)

| Benchmark | GPT-5.5 Pro | Mistral Medium 3.5 |
|---|---|---|
| LMArena Text | — | 1421 |
| LMArena Creative Writing | — | 1372 |
| EQ-Bench 4 | — | 993 |
| LMArena Multi-Turn | — | 1423 |

## FAQ

### Is GPT-5.5 Pro better than Mistral Medium 3.5?

GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 39.6 on the Noometry Index. Mistral Medium 3.5 costs 23× less per token, which makes it the better buy when GPT-5.5 Pro's lead doesn't matter for your workload.

### Which is cheaper, GPT-5.5 Pro or Mistral Medium 3.5?

Mistral Medium 3.5 is cheaper. It lists at $1.50 per million input tokens and $7.50 per million output tokens; GPT-5.5 Pro lists at $30 and $180.

### Which has the bigger context window?

GPT-5.5 Pro does, with 1.05M tokens against 262K.

### How many benchmarks do GPT-5.5 Pro and Mistral Medium 3.5 share?

1 benchmark has published results for both models. GPT-5.5 Pro has 14 scored results on Noometry and Mistral Medium 3.5 has 22.