Noometry

Model comparison

Claude Opus 5.5 vs GPT-4.5

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 37.2 on the Noometry Index.

Last verified . 20 shared benchmarks.

Claude Opus 5.5 Anthropic

68.6

Rank #3 Confirmed

GPT-4.5 OpenAI

37.2

Rank #208 Confirmed

Summary

  • They share 20 benchmarks with published results for both. Claude Opus 5.5 scores higher in 10 categories and GPT-4.5 in 0 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 5.5 leads 80.2 to 13.9.
  • The biggest single-benchmark swing is ARC-AGI-2: 93.3% for Claude Opus 5.5 and 0.8% for GPT-4.5.

Side by side

Claude Opus 5.5GPT-4.5
ProviderAnthropicOpenAI
Noometry Index68.637.2
Released2026-09-222025-02-27
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$4—
Output $ / M tokens$20—
Results tracked4442

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Category by category

Coding Claude Opus 5.5 leads

Claude Opus 5.5: 71.9 (#3), GPT-4.5: 42.2 (#109)

BenchmarkClaude Opus 5.5GPT-4.5
LMArena Coding15471396
FrontierCode54.6%—
Aider Polyglot—44.9%
CursorBench57.8%—
LMArena WebDev1813—
FrontierSWE62.3%—
SciCode66.9%—
WeirdML—39.4%
LiveBench Coding—75.2%
MirrorCode77.4%—
ALE-Bench2,147—

Agentic & Tool Use Claude Opus 5.5 leads

Claude Opus 5.5: 45.3 (#15), GPT-4.5: 27.9 (#97)

BenchmarkClaude Opus 5.5GPT-4.5
APEX-Agents73.5%—
Cybench—17.5%
GDP.pdf30.6%—
Vending-Bench 29,235—

Reasoning Claude Opus 5.5 leads

Claude Opus 5.5: 80.2 (#3), GPT-4.5: 13.9 (#330)

BenchmarkClaude Opus 5.5GPT-4.5
ARC-AGI-293.3%0.8%
ARC-AGI-198.5%10.3%
LMArena Hard Prompts15351403
Epoch Capabilities Index167.33136.74
SimpleBench—34.5%
NYT Connections (extended)88.5%—
CritPt31.7%—
EnigmaEval—3.2%
EBR-Bench71.4%—
LiveBench Reasoning—71.1%
Mystery Game Puzzles71%—
DTBench98.9%—
LiveBench Data Analysis—64.3%
LMCA68.2%—
ForecastBench—61.7
LiveBench—69%

Math Claude Opus 5.5 leads

Claude Opus 5.5: 91.8 (#3), GPT-4.5: 32.6 (#211)

BenchmarkClaude Opus 5.5GPT-4.5
OTIS Mock AIME 2024-2025100%37.8%
LMArena Math15061412
FrontierMath (Tiers 1-3)91.2%—
FrontierMath Tier 495%—
ProofBench100%—
LiveBench Math—69.3%
MATH Level 5—78.6%
FrontierMath Erdős2.9%—

Knowledge Claude Opus 5.5 leads

Claude Opus 5.5: 66.4 (#10), GPT-4.5: 32.5 (#211)

BenchmarkClaude Opus 5.5GPT-4.5
GPQA Diamond90.6%68.7%
LMArena Expert15471394
Humanity's Last Exam—5.4%
SimpleQA Verified72.2%—
Confabulations—13.6%

Multimodal Claude Opus 5.5 leads

Claude Opus 5.5: 57.8 (#1), GPT-4.5: 37.6 (#71)

BenchmarkClaude Opus 5.5GPT-4.5
LMArena Vision13211195
VPCT—45%
Blueprint-Bench 251.2%—
Furniture Assembly83.3%—

Multilingual Claude Opus 5.5 leads

Claude Opus 5.5: 59.1 (#2), GPT-4.5: 52.5 (#83)

BenchmarkClaude Opus 5.5GPT-4.5
LMArena Non-English15071413
LMArena Chinese15881421
LMArena French15141418
LMArena Russian15201419
LMArena German—1457
LMArena Japanese—1416
LMArena Korean—1392
LMArena Spanish1507—

Instruction Following Claude Opus 5.5 leads

Claude Opus 5.5: 80.0 (#3), GPT-4.5: 72.6 (#134)

BenchmarkClaude Opus 5.5GPT-4.5
LMArena Instruction Following15371404
LiveBench Instruction Following—72.3%

Long Context Claude Opus 5.5 leads

Claude Opus 5.5: 47.1 (#19), GPT-4.5: 40.4 (#155)

BenchmarkClaude Opus 5.5GPT-4.5
LMArena Longer Query15321406
Fiction.LiveBench—63.9%

Writing & Preference Claude Opus 5.5 leads

Claude Opus 5.5: 78.2 (#3), GPT-4.5: 56.9 (#134)

BenchmarkClaude Opus 5.5GPT-4.5
LMArena Text15151417
LMArena Creative Writing15331394
EQ-Bench Creative Writing20501258
LMArena Multi-Turn14991444
Short-Story Creative Writing—75.6%
LiveBench Language—61.5%

Frequently asked questions

Is Claude Opus 5.5 better than GPT-4.5?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 37.2 on the Noometry Index.

Is Claude Opus 5.5 or GPT-4.5 better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 42.2 in the Noometry coding category.

How many benchmarks do Claude Opus 5.5 and GPT-4.5 share?

20 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and GPT-4.5 has 42.

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