Noometry

Model comparison

Claude Opus 5.5 vs Grok 4

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 48.1 on the Noometry Index.

Last verified . 20 shared benchmarks.

Claude Opus 5.5 Anthropic

68.6

Rank #3 Confirmed

Grok 4 xAI

48.1

Rank #56 Confirmed

Summary

  • They share 20 benchmarks with published results for both. Claude Opus 5.5 scores higher in 9 categories and Grok 4 in 1 category; 9 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 5.5 leads 80.2 to 36.7.
  • The biggest single-benchmark swing is ARC-AGI-2: 93.3% for Claude Opus 5.5 and 16% for Grok 4.

Side by side

Claude Opus 5.5Grok 4
ProviderAnthropicxAI
Noometry Index68.648.1
Released2026-09-222025-07-09
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$4—
Output $ / M tokens$20—
Results tracked4448

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Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.9 (#3), Grok 4: 50.3 (#46)

BenchmarkClaude Opus 5.5Grok 4
LMArena Coding15471408
FrontierCode54.6%—
Aider Polyglot—79.6%
CursorBench57.8%—
LMArena WebDev1813—
FrontierSWE62.3%—
SciCode66.9%—
WeirdML—45.7%
MirrorCode77.4%—
ALE-Bench2,147—

Agentic & Tool Use Claude Opus 5.5 leads

Claude Opus 5.5: 45.3 (#15), Grok 4: 32.3 (#68)

BenchmarkClaude Opus 5.5Grok 4
Terminal-Bench—27.2%
APEX-Agents73.5%—
Berkeley Function Calling Leaderboard—63%
GDPval—21.1%
Cybench—43%
DeepResearch Bench—47.3%
BALROG—43.6%
GDP.pdf30.6%—
LMArena Search—1142
METR Time Horizons—66.6%
Vending-Bench 29,235—

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 80.2 (#3), Grok 4: 36.7 (#65)

BenchmarkClaude Opus 5.5Grok 4
ARC-AGI-293.3%16%
ARC-AGI-198.5%66.7%
LMArena Hard Prompts15351409
Epoch Capabilities Index167.33146.44
SimpleBench—60.5%
Kagi LLM Benchmark—73.6%
NYT Connections (extended)88.5%—
CritPt31.7%—
Chess Puzzles—28%
EBR-Bench71.4%—
Mystery Game Puzzles71%—
DTBench98.9%—
LMCA68.2%—
ForecastBench—60.9

Math Claude Opus 5.5 leads

Claude Opus 5.5: 91.8 (#3), Grok 4: 48.4 (#64)

BenchmarkClaude Opus 5.5Grok 4
OTIS Mock AIME 2024-2025100%84%
LMArena Math15061422
FrontierMath (Tiers 1-3)91.2%—
FrontierMath Tier 495%—
ProofBench100%—
Omni-MATH—60.3%
FrontierMath (Feb 2025 set)—19.7%
FrontierMath Erdős2.9%—
FrontierMath Tier 4 (v1)—2.1%

Knowledge Claude Opus 5.5 leads

Claude Opus 5.5: 66.4 (#10), Grok 4: 53.8 (#55)

BenchmarkClaude Opus 5.5Grok 4
GPQA Diamond90.6%87%
LMArena Expert15471415
SimpleQA Verified72.2%—
MMLU-Pro—85.1%
Confabulations—12.4%
GPQA (HELM)—72.7%

Multimodal Claude Opus 5.5 leads

Claude Opus 5.5: 57.8 (#1), Grok 4: 33.7 (#94)

BenchmarkClaude Opus 5.5Grok 4
LMArena Vision13211210
GeoBench—45%
Blueprint-Bench 251.2%—
Furniture Assembly83.3%—

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.1 (#2), Grok 4: 51.8 (#103)

BenchmarkClaude Opus 5.5Grok 4
LMArena Non-English15071403
LMArena Chinese15881427
LMArena French15141418
LMArena Russian15201410
LMArena Spanish15071420
LMArena German—1429
LMArena Japanese—1394
LMArena Korean—1377

Instruction Following Too close to call

Claude Opus 5.5: 80.0 (#3), Grok 4: 79.2 (#5)

BenchmarkClaude Opus 5.5Grok 4
LMArena Instruction Following15371387
IFEval—94.9%

Long Context Grok 4 leads

Claude Opus 5.5: 47.1 (#19), Grok 4: 63.1 (#4)

BenchmarkClaude Opus 5.5Grok 4
LMArena Longer Query15321409
Fiction.LiveBench—94.4%

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.2 (#3), Grok 4: 58.5 (#116)

BenchmarkClaude Opus 5.5Grok 4
LMArena Text15151411
LMArena Creative Writing15331397
LMArena Multi-Turn14991416
Short-Story Creative Writing—76.9%
EQ-Bench Creative Writing2050—
WildBench—79.7%

Frequently asked questions

Is Claude Opus 5.5 better than Grok 4?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 48.1 on the Noometry Index.

Is Claude Opus 5.5 or Grok 4 better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 50.3 in the Noometry coding category.

How many benchmarks do Claude Opus 5.5 and Grok 4 share?

20 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and Grok 4 has 48.

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