Noometry

Model comparison

Claude Sonnet 4.5 vs Mistral Small 3.1

Claude Sonnet 4.5 is the stronger model overall, scoring 44.0 to 31.4 on the Noometry Index. Mistral Small 3.1 costs 15× less per token, which makes it the better buy when Claude Sonnet 4.5's lead doesn't matter for your workload.

Last verified . 27 shared benchmarks.

Claude Sonnet 4.5 Anthropic

44.0

Rank #76 Confirmed

Mistral Small 3.1 Mistral AI

31.4

Rank #263 Confirmed

Summary

  • They share 27 benchmarks with published results for both. Claude Sonnet 4.5 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 writing & preference, where Claude Sonnet 4.5 leads 66.7 to 37.2.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 77.8% for Claude Sonnet 4.5 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 $3 / $15 for Claude Sonnet 4.5.
  • Claude Sonnet 4.5 accepts more context: 1M tokens versus 128K.
  • Mistral Small 3.1 has downloadable open weights; the other is API-only.

Side by side

Claude Sonnet 4.5Mistral Small 3.1
ProviderAnthropicMistral AI
Noometry Index44.031.4
Released2025-09-292025-03-17
WeightsProprietaryOpen
Context window1M128K
Max output64K102K
Input $ / M tokens$3$0.35
Output $ / M tokens$15$0.56
Results tracked7328

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Category by category

Coding Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 47.8 (#54), Mistral Small 3.1: 37.7 (#175)

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
LMArena Coding14891309
SWE-bench Verified71.3%—
SWE-bench Verified (bash only)71.4%—
LMArena WebDev1393—
SWE-bench Multilingual67%—
SciCode44.7%—
GSO14.7%—
WeirdML47.7%—
ALE-Bench796.15—
AlgoTune1.52—

Agentic & Tool Use Not comparable

Claude Sonnet 4.5: 38.1 (#30), Mistral Small 3.1: —

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
Terminal-Bench46.5%—
Berkeley Function Calling Leaderboard73.2%—
GDPval42.5%—
Remote Labor Index2.1%—
τ²-bench Airline72%—
τ²-bench Banking25.3%—
τ²-bench Retail72.4%—
τ²-bench Telecom84.9%—
Cybench60%—
DeepResearch Bench52.6%—
OSWorld62.9%—
LMArena Search1159—
METR Time Horizons67.4%—
Vending-Bench 23,839—

Reasoning Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 26.9 (#113), Mistral Small 3.1: 18.9 (#249)

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
Chess Puzzles12%1%
LMArena Hard Prompts14621278
Epoch Capabilities Index146.84127.48
ARC-AGI-213.6%—
SimpleBench54.3%—
Kagi LLM Benchmark57.9%—
NYT Connections (extended)37.3%—
ARC-AGI-163.7%—
CritPt1.1%—
EnigmaEval6%—
EBR-Bench2.4%—
Mystery Game Puzzles17%—
DTBench83.2%—
LMCA38.8%—
ForecastBench61.9—

Math Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 31.9 (#190), Mistral Small 3.1: 13.7 (#295)

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
OTIS Mock AIME 2024-202577.8%3.9%
Omni-MATH55.3%24.8%
LMArena Math14481261
FrontierMath (Tiers 1-3)23.9%—
FrontierMath Tier 42.4%—
ProofBench19%—
MATH Level 597.7%—
FrontierMath (Feb 2025 set)15.2%—
FrontierMath Tier 4 (v1)4.2%—

Knowledge Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 48.4 (#70), Mistral Small 3.1: 22.6 (#266)

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
GPQA Diamond82.3%41.9%
MMLU-Pro86.9%61%
GPQA (HELM)68.6%39.2%
LMArena Expert14831258
Humanity's Last Exam13.7%—
SimpleQA Verified30.7%—
Vectara Hallucination Rate12%—

Multimodal Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 34.1 (#84), Mistral Small 3.1: 32.6 (#93)

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
LMArena Vision—1136
VPCT39.8%—
LMArena Document1450—

Multilingual Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 53.6 (#65), Mistral Small 3.1: 41.4 (#204)

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
LMArena Non-English14251255
LMArena Chinese14591254
LMArena French14591270
LMArena German14271266
LMArena Japanese13901210
LMArena Korean14031206
LMArena Russian14361263
LMArena Spanish14571283

Instruction Following Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 75.2 (#74), Mistral Small 3.1: 63.8 (#225)

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
IFEval85%75%
LMArena Instruction Following14591264

Long Context Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 45.2 (#45), Mistral Small 3.1: 39.5 (#172)

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
LMArena Longer Query14761300

Writing & Preference Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 66.7 (#33), Mistral Small 3.1: 37.2 (#254)

BenchmarkClaude Sonnet 4.5Mistral Small 3.1
LMArena Text14391278
LMArena Creative Writing14421253
EQ-Bench Creative Writing1678761
WildBench85.4%78.8%
LMArena Multi-Turn14651270

Frequently asked questions

Is Claude Sonnet 4.5 better than Mistral Small 3.1?

Claude Sonnet 4.5 is the stronger model overall, scoring 44.0 to 31.4 on the Noometry Index. Mistral Small 3.1 costs 15× less per token, which makes it the better buy when Claude Sonnet 4.5's lead doesn't matter for your workload.

Which is cheaper, Claude Sonnet 4.5 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; Claude Sonnet 4.5 lists at $3 and $15.

Is Claude Sonnet 4.5 or Mistral Small 3.1 better for coding?

Claude Sonnet 4.5 scores higher on coding benchmarks: 47.8 versus 37.7 in the Noometry coding category.

Which has the bigger context window?

Claude Sonnet 4.5 does, with 1M tokens against 128K.

How many benchmarks do Claude Sonnet 4.5 and Mistral Small 3.1 share?

27 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and Mistral Small 3.1 has 28.

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