Noometry

Model comparison

Claude Opus 4.5 vs Grok 4.1 Fast

Claude Opus 4.5 is the stronger model overall, scoring 50.5 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 36× less per token, which makes it the better buy when Claude Opus 4.5's lead doesn't matter for your workload.

Last verified . 30 shared benchmarks.

Claude Opus 4.5 Anthropic

50.5

Rank #47 Confirmed

Grok 4.1 Fast xAI

41.4

Rank #136 Confirmed

Summary

  • They share 30 benchmarks with published results for both. Claude Opus 4.5 scores higher in 8 categories and Grok 4.1 Fast in 2 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Claude Opus 4.5 leads 56.5 to 33.1.
  • The biggest single-benchmark swing is NYT Connections (extended): 52.5% for Claude Opus 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 $5 / $25 for Claude Opus 4.5.
  • Claude Opus 4.5 accepts more context: 200K tokens versus 128K.

Side by side

Claude Opus 4.5Grok 4.1 Fast
ProviderAnthropicxAI
Noometry Index50.541.4
Released2025-11-012025-06-27
WeightsProprietaryProprietary
Context window200K128K
Max output64K30K
Input $ / M tokens$5$0.20
Output $ / M tokens$25$0.50
Results tracked6932

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Category by category

Coding Claude Opus 4.5 leads

Claude Opus 4.5: 54.8 (#27), Grok 4.1 Fast: 34.1 (#245)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
LMArena WebDev14941242
LMArena Coding15041411
ALE-Bench1,025394.93
SWE-bench Verified76.7%—
SWE-bench Verified (bash only)76.8%—
SWE-bench Multilingual70.7%—
GSO26.5%—
WeirdML63.7%—
AlgoTune1.77—

Agentic & Tool Use Claude Opus 4.5 leads

Claude Opus 4.5: 47.3 (#12), Grok 4.1 Fast: 36.3 (#39)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
Berkeley Function Calling Leaderboard77.5%69.6%
τ²-bench Banking24.7%13.1%
LMArena Search11801171
Vending-Bench 24,9671,107
Terminal-Bench63.1%—
GDPval45.5%—
Remote Labor Index3.8%—
τ²-bench Airline84%—
τ²-bench Retail79.6%—
τ²-bench Telecom92.3%—
Cybench82%—
DeepResearch Bench54.8%—
OSWorld66.3%—
BALROG43.5%—
METR Time Horizons75%—

Reasoning Too close to call

Claude Opus 4.5: 42.6 (#51), Grok 4.1 Fast: 43.4 (#49)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
SimpleBench62%56%
NYT Connections (extended)52.5%87.4%
LMArena Hard Prompts14761407
DTBench89.9%87.7%
ForecastBench60.761
ARC-AGI-237.6%—
Kagi LLM Benchmark80.2%—
ARC-AGI-180%—
Chess Puzzles12%—
EnigmaEval11.9%—
EBR-Bench14.3%—
Mystery Game Puzzles22%—
LMCA44.5%—
Epoch Capabilities Index150.09—

Math Claude Opus 4.5 leads

Claude Opus 4.5: 38.6 (#132), Grok 4.1 Fast: 31.9 (#221)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
ProofBench36%4%
LMArena Math14631408
FrontierMath (Tiers 1-3)34.4%—
FrontierMath Tier 44.9%—
MathArena Final-Answer Competitions—60.9%
OTIS Mock AIME 2024-202586.1%—
FrontierMath (Feb 2025 set)20.7%—
FrontierMath Tier 4 (v1)4.2%—

Knowledge Claude Opus 4.5 leads

Claude Opus 4.5: 56.5 (#44), Grok 4.1 Fast: 33.1 (#207)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
Vectara Hallucination Rate10.9%17.8%
LMArena Expert14871399
GPQA Diamond86%—
Humanity's Last Exam25.2%—
SimpleQA Verified45.7%—

Multimodal Grok 4.1 Fast leads

Claude Opus 4.5: 31.4 (#107), Grok 4.1 Fast: 37.0 (#76)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
LMArena Vision—1201
GeoBench75%—
VPCT40%—
Furniture Assembly28.3%—
LMArena Document1462—

Multilingual Claude Opus 4.5 leads

Claude Opus 4.5: 54.3 (#47), Grok 4.1 Fast: 51.0 (#114)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
LMArena Non-English14381391
LMArena Chinese14701441
LMArena French14711415
LMArena German14491404
LMArena Japanese14161349
LMArena Korean14241361
LMArena Russian14471387
LMArena Spanish14581413

Instruction Following Claude Opus 4.5 leads

Claude Opus 4.5: 77.5 (#19), Grok 4.1 Fast: 72.7 (#133)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
LMArena Instruction Following14781376

Long Context Claude Opus 4.5 leads

Claude Opus 4.5: 46.5 (#22), Grok 4.1 Fast: 42.4 (#126)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
LMArena Longer Query14801390
CL-bench21.1%—

Writing & Preference Claude Opus 4.5 leads

Claude Opus 4.5: 68.1 (#28), Grok 4.1 Fast: 57.2 (#131)

BenchmarkClaude Opus 4.5Grok 4.1 Fast
LMArena Text14511408
LMArena Creative Writing14451394
EQ-Bench Creative Writing16871327
LMArena Multi-Turn14661389

Frequently asked questions

Is Claude Opus 4.5 better than Grok 4.1 Fast?

Claude Opus 4.5 is the stronger model overall, scoring 50.5 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 36× less per token, which makes it the better buy when Claude Opus 4.5's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 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 Opus 4.5 lists at $5 and $25.

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

Claude Opus 4.5 scores higher on coding benchmarks: 54.8 versus 34.1 in the Noometry coding category.

Which has the bigger context window?

Claude Opus 4.5 does, with 200K tokens against 128K.

How many benchmarks do Claude Opus 4.5 and Grok 4.1 Fast share?

30 benchmarks have published results for both models. Claude Opus 4.5 has 69 scored results on Noometry and Grok 4.1 Fast has 32.

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