Model comparison

GPT-5.1 vs Mistral Small 3.1

GPT-5.1 is the stronger model overall, scoring 49.0 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 8.6× less per token, which makes it the better buy when GPT-5.1's lead doesn't matter for your workload.

Last verified . 27 shared benchmarks.

GPT-5.1 OpenAI

49.0

Rank #53 Confirmed

Mistral Small 3.1 Mistral AI

31.7

Rank #269 Confirmed

Summary

  • They share 27 benchmarks with published results for both. GPT-5.1 scores higher in 9 categories and Mistral Small 3.1 in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where GPT-5.1 leads 52.2 to 14.7.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 88.6% for GPT-5.1 and 3.9% for Mistral Small 3.1.
  • Mistral Small 3.1 is cheaper at $0.35 / $0.56 per million input/output tokens, against $1.25 / $10 for GPT-5.1.
  • GPT-5.1 accepts more context: 400K tokens versus 128K.
  • Mistral Small 3.1 has downloadable open weights; the other is API-only.

Side by side

GPT-5.1 and Mistral Small 3.1 specifications
GPT-5.1Mistral Small 3.1
ProviderOpenAIMistral AI
Noometry Index49.031.7
Released2025-11-132025-03-17
WeightsProprietaryOpen
Context window400K128K
Max output128K102K
Input $ / M tokens$1.25$0.35
Output $ / M tokens$10$0.56
Results tracked6328

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Category by category

Coding GPT-5.1 leads

GPT-5.1: 46.4 (#66), Mistral Small 3.1: 38.3 (#179)

Coding benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
LMArena Coding14541309
SWE-bench Verified68%—
SWE-bench Verified (bash only)66%—
LMArena WebDev1395—
SciCode43.3%—
GSO13.7%—
WeirdML60.8%—
LiveBench Coding72.5%—
ALE-Bench1,192—

Agentic & Tool Use Not comparable

GPT-5.1: 32.7 (#60), Mistral Small 3.1: —

Agentic & Tool Use benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
Terminal-Bench47.6%—
DeepResearch Bench42.8%—
LMArena Search1199—
Vending-Bench 21,473—

Reasoning GPT-5.1 leads

GPT-5.1: 39.8 (#58), Mistral Small 3.1: 19.7 (#254)

Reasoning benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
Chess Puzzles32%1%
LMArena Hard Prompts14571278
Epoch Capabilities Index149.64127.48
ARC-AGI-217.6%—
SimpleBench53.2%—
ARC-AGI-172.8%—
CritPt4.9%—
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 Small 3.1: 14.7 (#301)

Math benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
OTIS Mock AIME 2024-202588.6%3.9%
Omni-MATH46.4%24.8%
LMArena Math14471262
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 Small 3.1: 22.6 (#271)

Knowledge benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
GPQA Diamond87.6%41.9%
MMLU-Pro57.9%61%
GPQA (HELM)44.2%39.2%
LMArena Expert14701257
Humanity's Last Exam23.7%—
SimpleQA Verified48%—
Vectara Hallucination Rate10.9%—

Multimodal GPT-5.1 leads

GPT-5.1: 44.8 (#19), Mistral Small 3.1: 33.2 (#99)

Multimodal benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
LMArena Vision12501136
VPCT58.7%—
LMArena Document1403—

Multilingual GPT-5.1 leads

GPT-5.1: 53.8 (#56), Mistral Small 3.1: 41.2 (#209)

Multilingual benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
LMArena Non-English14311255
LMArena Chinese14951253
LMArena French14501273
LMArena German14381266
LMArena Japanese14531208
LMArena Korean14011206
LMArena Russian14351263
LMArena Spanish14331283

Instruction Following GPT-5.1 leads

GPT-5.1: 83.9 (#1), Mistral Small 3.1: 63.6 (#230)

Instruction Following benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
IFEval93.5%75%
LMArena Instruction Following14431264
LiveBench Instruction Following93.3%—

Long Context GPT-5.1 leads

GPT-5.1: 47.6 (#14), Mistral Small 3.1: 39.5 (#178)

Long Context benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
LMArena Longer Query14471299
CL-bench23.7%—
CL-bench Life17.3%—

Writing & Preference GPT-5.1 leads

GPT-5.1: 64.5 (#55), Mistral Small 3.1: 37.0 (#259)

Writing & Preference benchmarks
BenchmarkGPT-5.1Mistral Small 3.1
LMArena Text14431277
LMArena Creative Writing14271253
WildBench86.3%78.8%
LMArena Multi-Turn14501270
EQ-Bench Creative Writing—761
LiveBench Language80.2%—

Frequently asked questions

Is GPT-5.1 better than Mistral Small 3.1?

GPT-5.1 is the stronger model overall, scoring 49.0 to 31.7 on the Noometry Index. Mistral Small 3.1 costs 8.6× less per token, which makes it the better buy when GPT-5.1's lead doesn't matter for your workload.

Which is cheaper, GPT-5.1 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-5.1 lists at $1.25 and $10.

Is GPT-5.1 or Mistral Small 3.1 better for coding?

GPT-5.1 scores higher on coding benchmarks: 46.4 versus 38.3 in the Noometry coding category.

Which has the bigger context window?

GPT-5.1 does, with 400K tokens against 128K.

How many benchmarks do GPT-5.1 and Mistral Small 3.1 share?

27 benchmarks have published results for both models. GPT-5.1 has 63 scored results on Noometry and Mistral Small 3.1 has 28.

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