# GPT-5.3 Chat vs Mistral Small 3.1

> GPT-5.3 Chat is the stronger model overall, scoring 42.8 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 12× less per token, which makes it the better buy when GPT-5.3 Chat's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-5-3-chat-vs-mistral-small-3-1
- Last updated: 2026-10-10
- Shared benchmarks: 18

## Summary

- They share 18 benchmarks with published results for both. GPT-5.3 Chat scores higher in 8 categories and Mistral Small 3.1 in 0 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where GPT-5.3 Chat leads 63.1 to 37.0.
- Mistral Small 3.1 is cheaper at $0.35 / $0.56 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Chat.
- Mistral Small 3.1 has downloadable open weights; the other is API-only.

## Snapshot

| | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 42.8 | 31.7 |
| Rank | 109 | 269 |
| Context | 128K | 128K |
| Input $/M | $1.75 | $0.35 |
| Output $/M | $14 | $0.56 |
| Weights | Proprietary | Open |

## Coding

- GPT-5.3 Chat: 41.4 (#124)
- Mistral Small 3.1: 38.3 (#179)

| Benchmark | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| LMArena Coding | 1408 | 1309 |

## Reasoning

- GPT-5.3 Chat: 28.5 (#102)
- Mistral Small 3.1: 19.7 (#254)

| Benchmark | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| LMArena Hard Prompts | 1399 | 1278 |
| Chess Puzzles | — | 1% |
| Epoch Capabilities Index | — | 127.48 |

## Math

- GPT-5.3 Chat: 38.2 (#142)
- Mistral Small 3.1: 14.7 (#301)

| Benchmark | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| LMArena Math | 1389 | 1262 |
| OTIS Mock AIME 2024-2025 | — | 3.9% |
| Omni-MATH | — | 24.8% |

## Knowledge

- GPT-5.3 Chat: 38.8 (#140)
- Mistral Small 3.1: 22.6 (#271)

| Benchmark | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| LMArena Expert | 1397 | 1257 |
| GPQA Diamond | — | 41.9% |
| MMLU-Pro | — | 61% |
| GPQA (HELM) | — | 39.2% |

## Multimodal

- GPT-5.3 Chat: —
- Mistral Small 3.1: 33.2 (#99)

| Benchmark | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| LMArena Vision | — | 1136 |

## Multilingual

- GPT-5.3 Chat: 50.3 (#124)
- Mistral Small 3.1: 41.2 (#209)

| Benchmark | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| LMArena Non-English | 1382 | 1255 |
| LMArena Chinese | 1432 | 1253 |
| LMArena French | 1397 | 1273 |
| LMArena German | 1384 | 1266 |
| LMArena Japanese | 1352 | 1208 |
| LMArena Korean | 1346 | 1206 |
| LMArena Russian | 1400 | 1263 |
| LMArena Spanish | 1371 | 1283 |

## Instruction Following

- GPT-5.3 Chat: 72.8 (#129)
- Mistral Small 3.1: 63.6 (#230)

| Benchmark | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| LMArena Instruction Following | 1378 | 1264 |
| IFEval | — | 75% |

## Long Context

- GPT-5.3 Chat: 42.6 (#120)
- Mistral Small 3.1: 39.5 (#178)

| Benchmark | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| LMArena Longer Query | 1396 | 1299 |

## Writing & Preference

- GPT-5.3 Chat: 63.1 (#68)
- Mistral Small 3.1: 37.0 (#259)

| Benchmark | GPT-5.3 Chat | Mistral Small 3.1 |
|---|---|---|
| LMArena Text | 1389 | 1277 |
| LMArena Creative Writing | 1355 | 1253 |
| EQ-Bench Creative Writing | 1690 | 761 |
| LMArena Multi-Turn | 1412 | 1270 |
| WildBench | — | 78.8% |

## FAQ

### Is GPT-5.3 Chat better than Mistral Small 3.1?

GPT-5.3 Chat is the stronger model overall, scoring 42.8 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 12× less per token, which makes it the better buy when GPT-5.3 Chat's lead doesn't matter for your workload.

### Which is cheaper, GPT-5.3 Chat or Mistral Small 3.1?

Mistral Small 3.1 is cheaper. It lists at $0.35 per million input tokens and $0.56 per million output tokens; GPT-5.3 Chat lists at $1.75 and $14.

### Is GPT-5.3 Chat or Mistral Small 3.1 better for coding?

GPT-5.3 Chat scores higher on coding benchmarks: 41.4 versus 38.3 in the Noometry coding category.

### Which has the bigger context window?

Both accept 128K tokens.

### How many benchmarks do GPT-5.3 Chat and Mistral Small 3.1 share?

18 benchmarks have published results for both models. GPT-5.3 Chat has 18 scored results on Noometry and Mistral Small 3.1 has 28.