# GPT-5.5 Pro vs Mistral Small 3

> GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 30.9 on the Noometry Index. Mistral Small 3 costs 1174× 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-small-3
- Last updated: 2026-10-10
- Shared benchmarks: 4

## Summary

- They share 4 benchmarks with published results for both. GPT-5.5 Pro scores higher in 3 categories and Mistral Small 3 in 0 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.5 Pro leads 83.8 to 15.3.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 100% for GPT-5.5 Pro and 6.7% for Mistral Small 3.
- Mistral Small 3 is cheaper at $0.05 / $0.08 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
- GPT-5.5 Pro accepts more context: 1.05M tokens versus 33K.
- Mistral Small 3 has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.5 Pro | Mistral Small 3 |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 64.3 | 30.9 |
| Rank | 7 | 268 |
| Context | 1.05M | 33K |
| Input $/M | $30 | $0.05 |
| Output $/M | $180 | $0.08 |
| Weights | Proprietary | Open |

## Coding

- GPT-5.5 Pro: —
- Mistral Small 3: 36.0 (#203)

| Benchmark | GPT-5.5 Pro | Mistral Small 3 |
|---|---|---|
| BigCodeBench Instruct | — | 45.3% |
| LMArena Coding | — | 1246 |
| BigCodeBench Complete | — | 50.4% |

## Reasoning

- GPT-5.5 Pro: 73.6 (#7)
- Mistral Small 3: 18.2 (#269)

| Benchmark | GPT-5.5 Pro | Mistral Small 3 |
|---|---|---|
| Chess Puzzles | 64% | 0% |
| Epoch Capabilities Index | 162.45 | 127.06 |
| ARC-AGI-2 | 84.6% | — |
| SimpleBench | 76.9% | — |
| ARC-AGI-1 | 96.5% | — |
| CritPt | 30.6% | — |
| LMArena Hard Prompts | — | 1233 |
| DTBench | 96% | — |
| LMCA | 53.9% | — |

## Math

- GPT-5.5 Pro: 83.8 (#8)
- Mistral Small 3: 15.3 (#290)

| Benchmark | GPT-5.5 Pro | Mistral Small 3 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 6.7% |
| FrontierMath (Tiers 1-3) | 87.7% | — |
| FrontierMath Tier 4 | 78% | — |
| LMArena Math | — | 1240 |
| FrontierMath (Feb 2025 set) | 52.4% | — |
| FrontierMath Tier 4 (v1) | 39.6% | — |

## Knowledge

- GPT-5.5 Pro: 64.2 (#17)
- Mistral Small 3: 25.0 (#258)

| Benchmark | GPT-5.5 Pro | Mistral Small 3 |
|---|---|---|
| GPQA Diamond | 93.9% | 47.3% |
| Confabulations | — | 25.2% |
| LMArena Expert | — | 1202 |

## Multilingual

- GPT-5.5 Pro: —
- Mistral Small 3: 37.5 (#231)

| Benchmark | GPT-5.5 Pro | 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

- GPT-5.5 Pro: —
- Mistral Small 3: 63.9 (#224)

| Benchmark | GPT-5.5 Pro | Mistral Small 3 |
|---|---|---|
| LMArena Instruction Following | — | 1214 |

## Long Context

- GPT-5.5 Pro: —
- Mistral Small 3: 37.8 (#206)

| Benchmark | GPT-5.5 Pro | Mistral Small 3 |
|---|---|---|
| LMArena Longer Query | — | 1246 |

## Writing & Preference

- GPT-5.5 Pro: —
- Mistral Small 3: 32.4 (#275)

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

## FAQ

### Is GPT-5.5 Pro better than Mistral Small 3?

GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 30.9 on the Noometry Index. Mistral Small 3 costs 1174× 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 Small 3?

Mistral Small 3 is cheaper. It lists at $0.05 per million input tokens and $0.08 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 33K.

### How many benchmarks do GPT-5.5 Pro and Mistral Small 3 share?

4 benchmarks have published results for both models. GPT-5.5 Pro has 14 scored results on Noometry and Mistral Small 3 has 24.