# GPT-5.5 Instant vs Mistral Small

> GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 33.1 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-5-instant-vs-mistral-small
- Last updated: 2026-10-10
- Shared benchmarks: 22

## Summary

- They share 22 benchmarks with published results for both. GPT-5.5 Instant scores higher in 9 categories and Mistral Small in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where GPT-5.5 Instant leads 48.9 to 30.9.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 68.1% for GPT-5.5 Instant and 5.8% for Mistral Small.
- Mistral Small has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 42.5 | 33.1 |
| Rank | 99 | 238 |
| Context | — | 256K |
| Input $/M | — | $0.15 |
| Output $/M | — | $0.60 |
| Weights | Proprietary | Open |

## Coding

- GPT-5.5 Instant: 43.7 (#73)
- Mistral Small: 33.5 (#242)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| SciCode | 48.6% | 26.5% |
| LMArena Coding | 1433 | 1363 |
| BigCodeBench Instruct | — | 36.1% |
| LiveBench Coding | — | 36.2% |
| BigCodeBench Complete | — | 46.6% |
| ALE-Bench | — | 497.62 |

## Agentic & Tool Use

- GPT-5.5 Instant: —
- Mistral Small: 27.9 (#87)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| Berkeley Function Calling Leaderboard | — | 37.1% |

## Reasoning

- GPT-5.5 Instant: 24.2 (#149)
- Mistral Small: 19.3 (#238)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| CritPt | 0% | 0% |
| LMArena Hard Prompts | 1426 | 1336 |
| Kagi LLM Benchmark | — | 37.8% |
| Chess Puzzles | 12% | — |
| LiveBench Reasoning | — | 44.8% |
| DTBench | — | 70.9% |
| LiveBench Data Analysis | — | 53.7% |
| LMCA | — | 20.6% |
| Epoch Capabilities Index | 142.48 | — |
| LiveBench | — | 44% |

## Math

- GPT-5.5 Instant: 26.1 (#241)
- Mistral Small: 15.4 (#287)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 68.1% | 5.8% |
| LMArena Math | 1420 | 1341 |
| FrontierMath (Tiers 1-3) | 26.3% | — |
| FrontierMath Tier 4 | 2.4% | — |
| LiveBench Math | — | 39.9% |
| MATH Level 5 | — | 46.8% |

## Knowledge

- GPT-5.5 Instant: 48.9 (#68)
- Mistral Small: 30.9 (#214)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| GPQA Diamond | 82.5% | 47.5% |
| LMArena Expert | 1409 | 1293 |
| Vectara Hallucination Rate | — | 5.1% |
| MMLU | — | 68.7% |

## Multimodal

- GPT-5.5 Instant: 39.3 (#48)
- Mistral Small: 32.9 (#91)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| LMArena Vision | 1250 | 1142 |
| LMArena Document | 1403 | — |

## Multilingual

- GPT-5.5 Instant: 53.0 (#76)
- Mistral Small: 45.7 (#164)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| LMArena Non-English | 1417 | 1315 |
| LMArena Chinese | 1457 | 1342 |
| LMArena French | 1428 | 1337 |
| LMArena German | 1410 | 1341 |
| LMArena Japanese | 1408 | 1275 |
| LMArena Korean | 1393 | 1260 |
| LMArena Russian | 1430 | 1324 |
| LMArena Spanish | 1430 | 1346 |

## Instruction Following

- GPT-5.5 Instant: 74.4 (#94)
- Mistral Small: 66.6 (#204)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| LMArena Instruction Following | 1407 | 1310 |
| LiveBench Instruction Following | — | 63.7% |

## Long Context

- GPT-5.5 Instant: 43.4 (#92)
- Mistral Small: 40.4 (#151)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| LMArena Longer Query | 1422 | 1327 |

## Writing & Preference

- GPT-5.5 Instant: 62.0 (#81)
- Mistral Small: 52.6 (#165)

| Benchmark | GPT-5.5 Instant | Mistral Small |
|---|---|---|
| LMArena Text | 1419 | 1338 |
| LMArena Creative Writing | 1420 | 1304 |
| LMArena Multi-Turn | 1434 | 1344 |
| LiveBench Language | — | 30.5% |

## FAQ

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

GPT-5.5 Instant is the stronger model overall, scoring 42.5 to 33.1 on the Noometry Index.

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

GPT-5.5 Instant scores higher on coding benchmarks: 43.7 versus 33.5 in the Noometry coding category.

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

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