Noometry

Model comparison

Claude Sonnet 4.5 vs Grok 4.1 Fast

Claude Sonnet 4.5 is the stronger model overall, scoring 44.0 to 40.9 on the Noometry Index. Grok 4.1 Fast costs 22× less per token, which makes it the better buy when Claude Sonnet 4.5's lead doesn't matter for your workload.

Last verified . 30 shared benchmarks.

Claude Sonnet 4.5 Anthropic

44.0

Rank #76 Confirmed

Grok 4.1 Fast xAI

40.9

Rank #131 Confirmed

Summary

  • They share 30 benchmarks with published results for both. Claude Sonnet 4.5 scores higher in 8 categories and Grok 4.1 Fast in 2 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Claude Sonnet 4.5 leads 48.4 to 32.6.
  • The biggest single-benchmark swing is NYT Connections (extended): 37.3% for Claude Sonnet 4.5 and 87.4% for Grok 4.1 Fast.
  • Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.5.
  • Claude Sonnet 4.5 accepts more context: 1M tokens versus 128K.

Side by side

Claude Sonnet 4.5Grok 4.1 Fast
ProviderAnthropicxAI
Noometry Index44.040.9
Released2025-09-292025-06-27
WeightsProprietaryProprietary
Context window1M128K
Max output64K30K
Input $ / M tokens$3$0.20
Output $ / M tokens$15$0.50
Results tracked7332

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Category by category

Coding Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 47.8 (#54), Grok 4.1 Fast: 33.8 (#236)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
LMArena WebDev13931241
LMArena Coding14891411
ALE-Bench796.15394.93
SWE-bench Verified71.3%—
SWE-bench Verified (bash only)71.4%—
SWE-bench Multilingual67%—
SciCode44.7%—
GSO14.7%—
WeirdML47.7%—
AlgoTune1.52—

Agentic & Tool Use Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 38.1 (#30), Grok 4.1 Fast: 36.1 (#35)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
Berkeley Function Calling Leaderboard73.2%69.6%
τ²-bench Banking25.3%13.1%
LMArena Search11591171
Vending-Bench 23,8391,107
Terminal-Bench46.5%—
GDPval42.5%—
Remote Labor Index2.1%—
τ²-bench Airline72%—
τ²-bench Retail72.4%—
τ²-bench Telecom84.9%—
Cybench60%—
DeepResearch Bench52.6%—
OSWorld62.9%—
METR Time Horizons67.4%—

Reasoning Grok 4.1 Fast leads

Claude Sonnet 4.5: 26.9 (#113), Grok 4.1 Fast: 42.3 (#45)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
SimpleBench54.3%56%
NYT Connections (extended)37.3%87.4%
LMArena Hard Prompts14621407
DTBench83.2%87.7%
ForecastBench61.961
ARC-AGI-213.6%—
Kagi LLM Benchmark57.9%—
ARC-AGI-163.7%—
CritPt1.1%—
Chess Puzzles12%—
EnigmaEval6%—
EBR-Bench2.4%—
Mystery Game Puzzles17%—
LMCA38.8%—
Epoch Capabilities Index146.84—

Math Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 31.9 (#190), Grok 4.1 Fast: 30.9 (#201)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
ProofBench19%4%
LMArena Math14481408
FrontierMath (Tiers 1-3)23.9%—
FrontierMath Tier 42.4%—
MathArena Final-Answer Competitions—60.9%
OTIS Mock AIME 2024-202577.8%—
Omni-MATH55.3%—
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), Grok 4.1 Fast: 32.6 (#203)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
Vectara Hallucination Rate12%17.8%
LMArena Expert14831398
GPQA Diamond82.3%—
Humanity's Last Exam13.7%—
SimpleQA Verified30.7%—
MMLU-Pro86.9%—
GPQA (HELM)68.6%—

Multimodal Grok 4.1 Fast leads

Claude Sonnet 4.5: 34.1 (#84), Grok 4.1 Fast: 36.3 (#71)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
LMArena Vision—1201
VPCT39.8%—
LMArena Document1450—

Multilingual Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 53.6 (#65), Grok 4.1 Fast: 51.1 (#110)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
LMArena Non-English14251391
LMArena Chinese14591441
LMArena French14591416
LMArena German14271404
LMArena Japanese13901347
LMArena Korean14031361
LMArena Russian14361387
LMArena Spanish14571411

Instruction Following Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 75.2 (#74), Grok 4.1 Fast: 72.8 (#127)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
LMArena Instruction Following14591376
IFEval85%—

Long Context Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 45.2 (#45), Grok 4.1 Fast: 42.4 (#121)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
LMArena Longer Query14761390

Writing & Preference Claude Sonnet 4.5 leads

Claude Sonnet 4.5: 66.7 (#33), Grok 4.1 Fast: 57.4 (#126)

BenchmarkClaude Sonnet 4.5Grok 4.1 Fast
LMArena Text14391408
LMArena Creative Writing14421394
EQ-Bench Creative Writing16781327
LMArena Multi-Turn14651389
WildBench85.4%—

Frequently asked questions

Is Claude Sonnet 4.5 better than Grok 4.1 Fast?

Claude Sonnet 4.5 is the stronger model overall, scoring 44.0 to 40.9 on the Noometry Index. Grok 4.1 Fast costs 22× 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 Grok 4.1 Fast?

Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Claude Sonnet 4.5 lists at $3 and $15.

Is Claude Sonnet 4.5 or Grok 4.1 Fast better for coding?

Claude Sonnet 4.5 scores higher on coding benchmarks: 47.8 versus 33.8 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 Grok 4.1 Fast share?

30 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and Grok 4.1 Fast has 32.

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