Noometry

Model comparison

Claude Opus 4.8 vs Grok 4.5

Claude Opus 4.8 is the stronger model overall, scoring 60.7 to 55.0 on the Noometry Index. Grok 4.5 costs 3.3× less per token, which makes it the better buy when Claude Opus 4.8's lead doesn't matter for your workload.

Last verified . 52 shared benchmarks.

Claude Opus 4.8 Anthropic

60.7

Rank #13 Confirmed

Grok 4.5 xAI

55.0

Rank #25 Confirmed

Summary

  • They share 52 benchmarks with published results for both. Claude Opus 4.8 scores higher in 9 categories and Grok 4.5 in 1 category; 8 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Opus 4.8 leads 78.4 to 60.9.
  • The biggest single-benchmark swing is ProofBench: 69% for Claude Opus 4.8 and 31% for Grok 4.5.
  • Grok 4.5 is cheaper at $2 / $6 per million input/output tokens, against $5 / $25 for Claude Opus 4.8.
  • Claude Opus 4.8 accepts more context: 1M tokens versus 500K.

Side by side

Claude Opus 4.8Grok 4.5
ProviderAnthropicxAI
Noometry Index60.755.0
Released2026-05-282026-07-08
WeightsProprietaryProprietary
Context window1M500K
Max output128K500K
Input $ / M tokens$5$2
Output $ / M tokens$25$6
Results tracked6552

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Category by category

Coding Claude Opus 4.8 leads

Claude Opus 4.8: 59.9 (#12), Grok 4.5: 52.2 (#35)

BenchmarkClaude Opus 4.8Grok 4.5
DeepSWE59%53.8%
FrontierCode46.5%42.4%
LMArena WebDev15561553
SciCode53.5%54.1%
WeirdML82.9%46.4%
LMArena Coding14901474
ALE-Bench1,5641,309
GSO47.1%—

Agentic & Tool Use Claude Opus 4.8 leads

Claude Opus 4.8: 47.6 (#11), Grok 4.5: 44.4 (#17)

BenchmarkClaude Opus 4.8Grok 4.5
APEX-Agents48.9%56.2%
τ²-bench Banking39.7%47.9%
PostTrainBench33.8%23.4%
GBAEval70.9%65.4%
GDP.pdf24%14%
LMArena Search12041213
Vending-Bench 25,7873,887
OSWorld 2.020.6%—
Remote Labor Index8.3%—
DeepResearch Bench50.2%—

Reasoning Claude Opus 4.8 leads

Claude Opus 4.8: 64.7 (#16), Grok 4.5: 56.1 (#25)

BenchmarkClaude Opus 4.8Grok 4.5
ARC-AGI-272.1%52.6%
SimpleBench64.8%70%
Kagi LLM Benchmark88.8%83.5%
NYT Connections (extended)91.1%79.9%
ARC-AGI-192.5%87.2%
CritPt20.9%15.4%
Chess Puzzles34%36%
LMArena Hard Prompts14821462
DTBench94.9%96.5%
LMCA57.5%45.2%
Surface Evolver Bench87.5%74.4%
Epoch Capabilities Index158.21153.92
EnigmaEval23.5%—
EBR-Bench28.6%—
Mystery Game Puzzles36%—
Bench to the Future 30.14—
ForecastBench59.9—

Math Claude Opus 4.8 leads

Claude Opus 4.8: 78.4 (#13), Grok 4.5: 60.9 (#35)

BenchmarkClaude Opus 4.8Grok 4.5
FrontierMath (Tiers 1-3)80%57.2%
FrontierMath Tier 456.1%24.4%
OTIS Mock AIME 2024-202598.3%97.8%
ProofBench69%31%
LMArena Math14871459
MathArena Final-Answer Competitions91.8%—
FrontierMath (Feb 2025 set)47.2%—
FrontierMath Tier 4 (v1)31.3%—

Knowledge Grok 4.5 leads

Claude Opus 4.8: 61.3 (#29), Grok 4.5: 62.3 (#24)

BenchmarkClaude Opus 4.8Grok 4.5
GPQA Diamond91%93.4%
SimpleQA Verified53%48.3%
LMArena Expert15021466

Multimodal Claude Opus 4.8 leads

Claude Opus 4.8: 42.9 (#26), Grok 4.5: 37.6 (#72)

BenchmarkClaude Opus 4.8Grok 4.5
LMArena Vision12941288
Blueprint-Bench 214.5%27.3%
Furniture Assembly42.5%22.5%
LMArena Document14751452

Multilingual Too close to call

Claude Opus 4.8: 55.2 (#33), Grok 4.5: 54.4 (#42)

BenchmarkClaude Opus 4.8Grok 4.5
LMArena Non-English14501440
LMArena Chinese15071496
LMArena French14811456
LMArena German14721446
LMArena Japanese14401428
LMArena Korean14321404
LMArena Russian14741448
LMArena Spanish14661450

Instruction Following Claude Opus 4.8 leads

Claude Opus 4.8: 77.4 (#24), Grok 4.5: 76.0 (#48)

BenchmarkClaude Opus 4.8Grok 4.5
LMArena Instruction Following14761446

Long Context Too close to call

Claude Opus 4.8: 45.4 (#35), Grok 4.5: 44.8 (#56)

BenchmarkClaude Opus 4.8Grok 4.5
LMArena Longer Query14831463

Writing & Preference Claude Opus 4.8 leads

Claude Opus 4.8: 72.0 (#16), Grok 4.5: 65.8 (#42)

BenchmarkClaude Opus 4.8Grok 4.5
LMArena Text14611448
LMArena Creative Writing14541442
EQ-Bench Creative Writing18401579
LMArena Multi-Turn14761456
EQ-Bench 41281—

Frequently asked questions

Is Claude Opus 4.8 better than Grok 4.5?

Claude Opus 4.8 is the stronger model overall, scoring 60.7 to 55.0 on the Noometry Index. Grok 4.5 costs 3.3× less per token, which makes it the better buy when Claude Opus 4.8's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 4.8 or Grok 4.5?

Grok 4.5 is cheaper. It lists at $2 per million input tokens and $6 per million output tokens; Claude Opus 4.8 lists at $5 and $25.

Is Claude Opus 4.8 or Grok 4.5 better for coding?

Claude Opus 4.8 scores higher on coding benchmarks: 59.9 versus 52.2 in the Noometry coding category.

Which has the bigger context window?

Claude Opus 4.8 does, with 1M tokens against 500K.

How many benchmarks do Claude Opus 4.8 and Grok 4.5 share?

52 benchmarks have published results for both models. Claude Opus 4.8 has 65 scored results on Noometry and Grok 4.5 has 52.

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