Noometry

Model comparison

Claude Sonnet 5 vs Grok 4 Fast

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 39.4 on the Noometry Index.

Last verified . 23 shared benchmarks.

Claude Sonnet 5 Anthropic

54.6

Rank #29 Confirmed

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Summary

  • They share 23 benchmarks with published results for both. Claude Sonnet 5 scores higher in 8 categories and Grok 4 Fast in 1 category; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Sonnet 5 leads 66.2 to 38.9.
  • The biggest single-benchmark swing is WeirdML: 68.8% for Claude Sonnet 5 and 42.9% for Grok 4 Fast.

Side by side

Claude Sonnet 5Grok 4 Fast
ProviderAnthropicxAI
Noometry Index54.639.4
Released2026-06-292025-09-19
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$2—
Output $ / M tokens$10—
Results tracked5130

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Category by category

Coding Claude Sonnet 5 leads

Claude Sonnet 5: 55.5 (#26), Grok 4 Fast: 32.5 (#271)

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena WebDev15411159
WeirdML68.8%42.9%
LMArena Coding14831429
DeepSWE53.8%—
FrontierCode42.7%—
CursorBench34.1%—
SciCode54.3%—
GSO37.3%—
ALE-Bench1,463—

Agentic & Tool Use Claude Sonnet 5 leads

Claude Sonnet 5: 42.8 (#18), Grok 4 Fast: 29.5 (#86)

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena Search11941171
APEX-Agents54.5%—
τ²-bench Banking—15.7%
Cybench—30%
GBAEval65.3%—
Vending-Bench 26,378—

Reasoning Claude Sonnet 5 leads

Claude Sonnet 5: 49.1 (#39), Grok 4 Fast: 22.2 (#201)

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena Hard Prompts14611412
DTBench92.5%82.7%
Epoch Capabilities Index156.21144.2
ForecastBench61.160.5
ARC-AGI-2—5.3%
SimpleBench60.6%—
Kagi LLM Benchmark—66.1%
NYT Connections (extended)75.1%—
ARC-AGI-1—48.5%
CritPt16.9%—
Chess Puzzles35%—
Mystery Game Puzzles35%—
LMCA50%—
Surface Evolver Bench60%—
Bench to the Future 30.14—

Math Claude Sonnet 5 leads

Claude Sonnet 5: 66.2 (#27), Grok 4 Fast: 38.9 (#123)

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena Math14671419
FrontierMath (Tiers 1-3)65.6%—
FrontierMath Tier 429.3%—
OTIS Mock AIME 2024-202594.7%—
ProofBench77%—

Knowledge Claude Sonnet 5 leads

Claude Sonnet 5: 55.6 (#47), Grok 4 Fast: 32.0 (#214)

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena Expert14901411
GPQA Diamond90.5%—
SimpleQA Verified33.7%—
Vectara Hallucination Rate—19.7%

Multimodal Not comparable

Claude Sonnet 5: 42.4 (#31), Grok 4 Fast: —

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena Vision1274—
Blueprint-Bench 224.9%—
LMArena Document1466—

Multilingual Claude Sonnet 5 leads

Claude Sonnet 5: 53.8 (#55), Grok 4 Fast: 51.3 (#111)

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena Non-English14311396
LMArena Chinese14771457
LMArena French14601431
LMArena German14401383
LMArena Japanese14221352
LMArena Korean14111357
LMArena Russian14511389
LMArena Spanish14371415

Instruction Following Claude Sonnet 5 leads

Claude Sonnet 5: 76.3 (#41), Grok 4 Fast: 73.2 (#121)

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena Instruction Following14521387

Long Context Grok 4 Fast leads

Claude Sonnet 5: 44.8 (#55), Grok 4 Fast: 63.2 (#3)

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena Longer Query14631415
Fiction.LiveBench—94.4%

Writing & Preference Claude Sonnet 5 leads

Claude Sonnet 5: 69.2 (#25), Grok 4 Fast: 60.0 (#102)

BenchmarkClaude Sonnet 5Grok 4 Fast
LMArena Text14421407
LMArena Creative Writing14161387
LMArena Multi-Turn14541414
EQ-Bench Creative Writing1794—
EQ-Bench 41236—

Frequently asked questions

Is Claude Sonnet 5 better than Grok 4 Fast?

Claude Sonnet 5 is the stronger model overall, scoring 54.6 to 39.4 on the Noometry Index.

Is Claude Sonnet 5 or Grok 4 Fast better for coding?

Claude Sonnet 5 scores higher on coding benchmarks: 55.5 versus 32.5 in the Noometry coding category.

How many benchmarks do Claude Sonnet 5 and Grok 4 Fast share?

23 benchmarks have published results for both models. Claude Sonnet 5 has 51 scored results on Noometry and Grok 4 Fast has 30.

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