# GPT-5.1-Codex vs Mistral Medium 3.1

> GPT-5.1-Codex is the stronger model overall, scoring 38.2 to 31.5 on the Noometry Index. Mistral Medium 3.1 costs 4.3× less per token, which makes it the better buy when GPT-5.1-Codex's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-mistral-medium-3-1
- Last updated: 2026-10-10
- Shared benchmarks: 0

## Summary

- Mistral Medium 3.1 is cheaper at $0.40 / $2 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
- GPT-5.1-Codex accepts more context: 400K tokens versus 131K.

## Snapshot

| | GPT-5.1-Codex | Mistral Medium 3.1 |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 38.2 | 31.5 |
| Rank | 178 | 260 |
| Context | 400K | 131K |
| Input $/M | $1.25 | $0.40 |
| Output $/M | $10 | $2 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.1-Codex: 41.7 (#107)
- Mistral Medium 3.1: —

| Benchmark | GPT-5.1-Codex | Mistral Medium 3.1 |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| ALE-Bench | 1,245 | — |

## Agentic & Tool Use

- GPT-5.1-Codex: 37.8 (#32)
- Mistral Medium 3.1: —

| Benchmark | GPT-5.1-Codex | Mistral Medium 3.1 |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- Mistral Medium 3.1: 10.1 (#336)

| Benchmark | GPT-5.1-Codex | Mistral Medium 3.1 |
|---|---|---|
| NYT Connections (extended) | — | 6.5% |
| Thematic Generalization | — | 20.3% |

## Math

- GPT-5.1-Codex: 29.3 (#218)
- Mistral Medium 3.1: —

| Benchmark | GPT-5.1-Codex | Mistral Medium 3.1 |
|---|---|---|
| ProofBench | 9% | — |

## Writing & Preference

- GPT-5.1-Codex: —
- Mistral Medium 3.1: 55.6 (#140)

| Benchmark | GPT-5.1-Codex | Mistral Medium 3.1 |
|---|---|---|
| EQ-Bench Creative Writing | — | 1476 |

## FAQ

### Is GPT-5.1-Codex better than Mistral Medium 3.1?

GPT-5.1-Codex is the stronger model overall, scoring 38.2 to 31.5 on the Noometry Index. Mistral Medium 3.1 costs 4.3× less per token, which makes it the better buy when GPT-5.1-Codex's lead doesn't matter for your workload.

### Which is cheaper, GPT-5.1-Codex or Mistral Medium 3.1?

Mistral Medium 3.1 is cheaper. It lists at $0.40 per million input tokens and $2 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.

### Which has the bigger context window?

GPT-5.1-Codex does, with 400K tokens against 131K.

### How many benchmarks do GPT-5.1-Codex and Mistral Medium 3.1 share?

0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and Mistral Medium 3.1 has 3.