Model comparison

GPT-5.1-Codex vs Mistral Medium 3.1

GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 31.9 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.

Last verified . 0 shared benchmarks.

GPT-5.1-Codex OpenAI

38.6

Rank #186 Reported

Mistral Medium 3.1 Mistral AI

31.9

Rank #266 Reported

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.

Side by side

GPT-5.1-Codex and Mistral Medium 3.1 specifications
GPT-5.1-CodexMistral Medium 3.1
ProviderOpenAIMistral AI
Noometry Index38.631.9
Released2025-11-12—
WeightsProprietaryProprietary
Context window400K131K
Max output128K105K
Input $ / M tokens$1.25$0.40
Output $ / M tokens$10$2
Results tracked63

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Category by category

Coding Not comparable

GPT-5.1-Codex: 41.9 (#116), Mistral Medium 3.1: —

Coding benchmarks
BenchmarkGPT-5.1-CodexMistral Medium 3.1
SWE-bench Verified (bash only)66%—
LMArena WebDev1337—
ALE-Bench1,245—

Agentic & Tool Use Not comparable

GPT-5.1-Codex: 38.0 (#33), Mistral Medium 3.1: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.1-CodexMistral Medium 3.1
Terminal-Bench60.4%—
METR Time Horizons70.8%—

Reasoning Not comparable

GPT-5.1-Codex: —, Mistral Medium 3.1: 10.6 (#341)

Reasoning benchmarks
BenchmarkGPT-5.1-CodexMistral Medium 3.1
NYT Connections (extended)—6.5%
Thematic Generalization—20.3%

Math Not comparable

GPT-5.1-Codex: 30.3 (#235), Mistral Medium 3.1: —

Math benchmarks
BenchmarkGPT-5.1-CodexMistral Medium 3.1
ProofBench9%—

Writing & Preference Not comparable

GPT-5.1-Codex: —, Mistral Medium 3.1: 55.5 (#145)

Writing & Preference benchmarks
BenchmarkGPT-5.1-CodexMistral Medium 3.1
EQ-Bench Creative Writing—1476

Frequently asked questions

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

GPT-5.1-Codex is the stronger model overall, scoring 38.6 to 31.9 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.

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