Model comparison

GPT-5.1 vs Mistral Medium 3.5

GPT-5.1 is the stronger model overall, scoring 49.0 to 40.2 on the Noometry Index.

Last verified . 19 shared benchmarks.

GPT-5.1 OpenAI

49.0

Rank #53 Confirmed

Mistral Medium 3.5 Mistral AI

40.2

Rank #152 Confirmed

Summary

  • They share 19 benchmarks with published results for both. GPT-5.1 scores higher in 9 categories and Mistral Medium 3.5 in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.1 leads 39.8 to 17.3.
  • Mistral Medium 3.5 is cheaper at $1.50 / $7.50 per million input/output tokens, against $1.25 / $10 for GPT-5.1.
  • GPT-5.1 accepts more context: 400K tokens versus 262K.
  • Mistral Medium 3.5 has downloadable open weights; the other is API-only.

Side by side

GPT-5.1 and Mistral Medium 3.5 specifications
GPT-5.1Mistral Medium 3.5
ProviderOpenAIMistral AI
Noometry Index49.040.2
Released2025-11-13—
WeightsProprietaryOpen
Context window400K262K
Max output128K210K
Input $ / M tokens$1.25$1.50
Output $ / M tokens$10$7.50
Results tracked6322

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Category by category

Coding GPT-5.1 leads

GPT-5.1: 46.4 (#66), Mistral Medium 3.5: 36.0 (#213)

Coding benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
LMArena WebDev13951264
LMArena Coding14541461
SWE-bench Verified68%—
SWE-bench Verified (bash only)66%—
SciCode43.3%—
GSO13.7%—
WeirdML60.8%—
LiveBench Coding72.5%—
ALE-Bench1,192—

Agentic & Tool Use Not comparable

GPT-5.1: 32.7 (#60), Mistral Medium 3.5: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
Terminal-Bench47.6%—
DeepResearch Bench42.8%—
LMArena Search1199—
Vending-Bench 21,473—

Reasoning GPT-5.1 leads

GPT-5.1: 39.8 (#58), Mistral Medium 3.5: 17.3 (#295)

Reasoning benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
LMArena Hard Prompts14571436
Epoch Capabilities Index149.64141.35
ARC-AGI-217.6%—
SimpleBench53.2%—
Kagi LLM Benchmark—41.4%
NYT Connections (extended)—12.9%
ARC-AGI-172.8%—
CritPt4.9%—
Chess Puzzles32%—
EnigmaEval11.2%—
LiveBench Reasoning95.8%—
Mystery Game Puzzles19%—
DTBench90.1%—
LiveBench Data Analysis72.1%—
LMCA43.9%—
ForecastBench58.1—
LiveBench78.8%—

Math GPT-5.1 leads

GPT-5.1: 52.2 (#51), Mistral Medium 3.5: 39.1 (#113)

Math benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
LMArena Math14471431
OTIS Mock AIME 2024-202588.6%—
Omni-MATH46.4%—
LiveBench Math94.5%—
FrontierMath (Feb 2025 set)31%—
FrontierMath Tier 4 (v1)12.5%—

Knowledge GPT-5.1 leads

GPT-5.1: 50.6 (#71), Mistral Medium 3.5: 40.0 (#126)

Knowledge benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
LMArena Expert14701432
GPQA Diamond87.6%—
Humanity's Last Exam23.7%—
SimpleQA Verified48%—
MMLU-Pro57.9%—
Vectara Hallucination Rate10.9%—
GPQA (HELM)44.2%—

Multimodal GPT-5.1 leads

GPT-5.1: 44.8 (#19), Mistral Medium 3.5: 38.3 (#65)

Multimodal benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
LMArena Vision12501223
VPCT58.7%—
LMArena Document1403—

Multilingual GPT-5.1 leads

GPT-5.1: 53.8 (#56), Mistral Medium 3.5: 51.9 (#100)

Multilingual benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
LMArena Non-English14311404
LMArena Chinese14951442
LMArena French14501448
LMArena German14381451
LMArena Korean14011385
LMArena Russian14351395
LMArena Spanish14331409
LMArena Japanese1453—

Instruction Following GPT-5.1 leads

GPT-5.1: 83.9 (#1), Mistral Medium 3.5: 74.6 (#90)

Instruction Following benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
LMArena Instruction Following14431415
LiveBench Instruction Following93.3%—
IFEval93.5%—

Long Context GPT-5.1 leads

GPT-5.1: 47.6 (#14), Mistral Medium 3.5: 43.2 (#103)

Long Context benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
LMArena Longer Query14471415
CL-bench23.7%—
CL-bench Life17.3%—

Writing & Preference GPT-5.1 leads

GPT-5.1: 64.5 (#55), Mistral Medium 3.5: 58.5 (#117)

Writing & Preference benchmarks
BenchmarkGPT-5.1Mistral Medium 3.5
LMArena Text14431421
LMArena Creative Writing14271374
LMArena Multi-Turn14501423
WildBench86.3%—
EQ-Bench 4—993
LiveBench Language80.2%—

Frequently asked questions

Is GPT-5.1 better than Mistral Medium 3.5?

GPT-5.1 is the stronger model overall, scoring 49.0 to 40.2 on the Noometry Index.

Which is cheaper, GPT-5.1 or Mistral Medium 3.5?

Mistral Medium 3.5 is cheaper. It lists at $1.50 per million input tokens and $7.50 per million output tokens; GPT-5.1 lists at $1.25 and $10.

Is GPT-5.1 or Mistral Medium 3.5 better for coding?

GPT-5.1 scores higher on coding benchmarks: 46.4 versus 36.0 in the Noometry coding category.

Which has the bigger context window?

GPT-5.1 does, with 400K tokens against 262K.

How many benchmarks do GPT-5.1 and Mistral Medium 3.5 share?

19 benchmarks have published results for both models. GPT-5.1 has 63 scored results on Noometry and Mistral Medium 3.5 has 22.

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