# GPT-5.5 vs Mistral Small

> GPT-5.5 is the stronger model overall, scoring 63.4 to 33.4 on the Noometry Index. Mistral Small costs 43× less per token, which makes it the better buy when GPT-5.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-5-5-vs-mistral-small
- Last updated: 2026-10-11
- Shared benchmarks: 27

## Summary

- They share 27 benchmarks with published results for both. GPT-5.5 scores higher in 10 categories and Mistral Small in 0 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.5 leads 81.7 to 16.4.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 100% for GPT-5.5 and 5.8% for Mistral Small.
- Mistral Small is cheaper at $0.15 / $0.60 per million input/output tokens, against $5 / $30 for GPT-5.5.
- GPT-5.5 accepts more context: 1.05M tokens versus 262K.
- Mistral Small has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.5 | Mistral Small |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 63.4 | 33.4 |
| Rank | 9 | 243 |
| Context | 1.05M | 262K |
| Input $/M | $5 | $0.15 |
| Output $/M | $30 | $0.60 |
| Weights | Proprietary | Open |

## Coding

- GPT-5.5: 58.2 (#17)
- Mistral Small: 34.0 (#247)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| SciCode | 56.1% | 26.5% |
| LMArena Coding | 1494 | 1362 |
| ALE-Bench | 1,943 | 497.62 |
| SWE-bench Verified | 80.6% | — |
| DeepSWE | 67% | — |
| FrontierCode | 43% | — |
| LMArena WebDev | 1513 | — |
| GSO | 40.2% | — |
| WeirdML | 84.9% | — |
| BigCodeBench Instruct | — | 36.1% |
| LiveBench Coding | — | 36.2% |
| MirrorCode | 10% | — |
| BigCodeBench Complete | — | 46.6% |

## Agentic & Tool Use

- GPT-5.5: 50.7 (#6)
- Mistral Small: 28.1 (#93)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| Terminal-Bench | 84.7% | — |
| APEX-Agents | 55.1% | — |
| Berkeley Function Calling Leaderboard | — | 37.1% |
| OSWorld 2.0 | 13% | — |
| Remote Labor Index | 6.3% | — |
| τ²-bench Banking | 44.6% | — |
| DeepResearch Bench | 54% | — |
| PostTrainBench | 27.2% | — |
| ExploitBench | 47.4% | — |
| GBAEval | 53.2% | — |
| GDP.pdf | 26% | — |
| LMArena Search | 1242 | — |
| Vending-Bench 2 | 7,524 | — |

## Reasoning

- GPT-5.5: 72.8 (#11)
- Mistral Small: 19.8 (#250)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| Kagi LLM Benchmark | 88.8% | 37.8% |
| CritPt | 27.1% | 0% |
| LMArena Hard Prompts | 1489 | 1335 |
| DTBench | 96% | 70.9% |
| LMCA | 54.3% | 20.6% |
| ARC-AGI-2 | 85% | — |
| SimpleBench | 69% | — |
| NYT Connections (extended) | 96.2% | — |
| ARC-AGI-1 | 95% | — |
| Chess Puzzles | 54% | — |
| EBR-Bench | 34.3% | — |
| LiveBench Reasoning | — | 44.8% |
| Mystery Game Puzzles | 56% | — |
| LiveBench Data Analysis | — | 53.7% |
| Surface Evolver Bench | 88.1% | — |
| Bench to the Future 3 | 0.14 | — |
| Epoch Capabilities Index | 159.1 | — |
| ForecastBench | 60.6 | — |
| LiveBench | — | 44% |

## Math

- GPT-5.5: 81.7 (#11)
- Mistral Small: 16.4 (#293)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 5.8% |
| LMArena Math | 1486 | 1341 |
| FrontierMath (Tiers 1-3) | 85.3% | — |
| FrontierMath Tier 4 | 72.5% | — |
| MathArena Final-Answer Competitions | 94.3% | — |
| ProofBench | 50% | — |
| LiveBench Math | — | 39.9% |
| MATH Level 5 | — | 46.8% |
| FrontierMath (Feb 2025 set) | 51.7% | — |
| FrontierMath Erdős | 0% | — |
| FrontierMath Tier 4 (v1) | 35.4% | — |

## Knowledge

- GPT-5.5: 64.4 (#17)
- Mistral Small: 31.0 (#222)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| GPQA Diamond | 94% | 47.5% |
| Vectara Hallucination Rate | 9.3% | 5.1% |
| LMArena Expert | 1508 | 1291 |
| SimpleQA Verified | 63% | — |
| MMLU | — | 68.7% |

## Multimodal

- GPT-5.5: 46.9 (#12)
- Mistral Small: 33.5 (#96)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| LMArena Vision | 1297 | 1142 |
| Blueprint-Bench 2 | 36.2% | — |
| Furniture Assembly | 44.2% | — |
| LMArena Document | 1486 | — |

## Multilingual

- GPT-5.5: 56.4 (#20)
- Mistral Small: 45.5 (#169)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| LMArena Non-English | 1467 | 1315 |
| LMArena Chinese | 1533 | 1340 |
| LMArena French | 1486 | 1337 |
| LMArena German | 1480 | 1340 |
| LMArena Japanese | 1498 | 1275 |
| LMArena Korean | 1460 | 1259 |
| LMArena Russian | 1473 | 1324 |
| LMArena Spanish | 1468 | 1346 |

## Instruction Following

- GPT-5.5: 77.5 (#18)
- Mistral Small: 66.4 (#209)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| LMArena Instruction Following | 1479 | 1310 |
| LiveBench Instruction Following | — | 63.7% |

## Long Context

- GPT-5.5: 48.3 (#12)
- Mistral Small: 40.4 (#156)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| LMArena Longer Query | 1484 | 1327 |
| CL-bench Life | 22.2% | — |

## Writing & Preference

- GPT-5.5: 72.7 (#13)
- Mistral Small: 52.5 (#171)

| Benchmark | GPT-5.5 | Mistral Small |
|---|---|---|
| LMArena Text | 1472 | 1338 |
| LMArena Creative Writing | 1455 | 1305 |
| LMArena Multi-Turn | 1476 | 1344 |
| EQ-Bench Creative Writing | 1844 | — |
| EQ-Bench 4 | 1315 | — |
| LiveBench Language | — | 30.5% |

## FAQ

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

GPT-5.5 is the stronger model overall, scoring 63.4 to 33.4 on the Noometry Index. Mistral Small costs 43× less per token, which makes it the better buy when GPT-5.5's lead doesn't matter for your workload.

### Which is cheaper, GPT-5.5 or Mistral Small?

Mistral Small is cheaper. It lists at $0.15 per million input tokens and $0.60 per million output tokens; GPT-5.5 lists at $5 and $30.

### Is GPT-5.5 or Mistral Small better for coding?

GPT-5.5 scores higher on coding benchmarks: 58.2 versus 34.0 in the Noometry coding category.

### Which has the bigger context window?

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

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

27 benchmarks have published results for both models. GPT-5.5 has 71 scored results on Noometry and Mistral Small has 39.