Model comparison

Claude Fable 5 vs GPT-4.5

Claude Fable 5 is the stronger model overall, scoring 66.3 to 36.9 on the Noometry Index.

Last verified . 26 shared benchmarks.

Claude Fable 5 Anthropic

66.3

Rank #5 Confirmed

GPT-4.5 OpenAI

36.9

Rank #200 Confirmed

Summary

  • They share 26 benchmarks with published results for both. Claude Fable 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 Fable 5 leads 76.8 to 14.1.
  • The biggest single-benchmark swing is ARC-AGI-2: 89.2% for Claude Fable 5 and 0.8% for GPT-4.5.

Side by side

Claude Fable 5 and GPT-4.5 specifications
Claude Fable 5GPT-4.5
ProviderAnthropicOpenAI
Noometry Index66.336.9
Released2026-06-072025-02-27
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$10—
Output $ / M tokens$50—
Results tracked6142

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Category by category

Coding Claude Fable 5 leads

Claude Fable 5: 67.0 (#4), GPT-4.5: 41.8 (#102)

Coding benchmarks
BenchmarkClaude Fable 5GPT-4.5
WeirdML91.9%39.4%
LMArena Coding15191397
DeepSWE69.9%—
FrontierCode53.5%—
Aider Polyglot—44.9%
LMArena WebDev1626—
FrontierSWE47%—
SciCode61%—
LiveBench Coding—75.2%
MirrorCode63.9%—
ALE-Bench2,041—

Agentic & Tool Use Claude Fable 5 leads

Claude Fable 5: 54.1 (#2), GPT-4.5: 27.6 (#92)

Agentic & Tool Use benchmarks
BenchmarkClaude Fable 5GPT-4.5
APEX-Agents63.6%—
Remote Labor Index16.1%—
τ²-bench Banking39.7%—
Cybench—17.5%
PostTrainBench41.8%—
GBAEval74.5%—
GDP.pdf30%—
LMArena Search1230—
Vending-Bench 25,680—

Reasoning Claude Fable 5 leads

Claude Fable 5: 76.8 (#4), GPT-4.5: 14.1 (#320)

Reasoning benchmarks
BenchmarkClaude Fable 5GPT-4.5
ARC-AGI-289.2%0.8%
SimpleBench81.9%34.5%
ARC-AGI-198.5%10.3%
EnigmaEval39.3%3.2%
LMArena Hard Prompts15081404
Epoch Capabilities Index163.6136.74
Kagi LLM Benchmark91.4%—
NYT Connections (extended)92.7%—
CritPt28.6%—
Chess Puzzles41%—
EBR-Bench39.5%—
LiveBench Reasoning—71.1%
Mystery Game Puzzles52%—
DTBench98.4%—
LiveBench Data Analysis—64.3%
LMCA61.1%—
Surface Evolver Bench95%—
Bench to the Future 30.13—
ForecastBench—61.7
LiveBench—69%

Math Claude Fable 5 leads

Claude Fable 5: 88.4 (#5), GPT-4.5: 31.0 (#200)

Math benchmarks
BenchmarkClaude Fable 5GPT-4.5
OTIS Mock AIME 2024-2025100%37.8%
LMArena Math15191412
FrontierMath (Tiers 1-3)87%—
FrontierMath Tier 490.2%—
ProofBench95%—
LiveBench Math—69.3%
MATH Level 5—78.6%
FrontierMath Erdős0%—

Knowledge Claude Fable 5 leads

Claude Fable 5: 62.3 (#22), GPT-4.5: 32.4 (#205)

Knowledge benchmarks
BenchmarkClaude Fable 5GPT-4.5
GPQA Diamond85.9%68.7%
LMArena Expert15341394
Humanity's Last Exam—5.4%
SimpleQA Verified70.7%—
Confabulations—13.6%

Multimodal Claude Fable 5 leads

Claude Fable 5: 45.6 (#14), GPT-4.5: 37.0 (#68)

Multimodal benchmarks
BenchmarkClaude Fable 5GPT-4.5
LMArena Vision13261195
VPCT—45%
Blueprint-Bench 238.6%—
Furniture Assembly35.8%—
LMArena Document1496—

Multilingual Claude Fable 5 leads

Claude Fable 5: 57.6 (#8), GPT-4.5: 52.7 (#78)

Multilingual benchmarks
BenchmarkClaude Fable 5GPT-4.5
LMArena Non-English14831413
LMArena Chinese15461421
LMArena French15091417
LMArena German14861457
LMArena Japanese15071416
LMArena Korean14931392
LMArena Russian15071419
LMArena Spanish1503—

Instruction Following Claude Fable 5 leads

Claude Fable 5: 78.8 (#7), GPT-4.5: 72.8 (#129)

Instruction Following benchmarks
BenchmarkClaude Fable 5GPT-4.5
LMArena Instruction Following15031404
LiveBench Instruction Following—72.3%

Long Context Claude Fable 5 leads

Claude Fable 5: 46.3 (#22), GPT-4.5: 40.4 (#150)

Long Context benchmarks
BenchmarkClaude Fable 5GPT-4.5
LMArena Longer Query15101406
Fiction.LiveBench—63.9%

Writing & Preference Claude Fable 5 leads

Claude Fable 5: 76.1 (#5), GPT-4.5: 57.1 (#129)

Writing & Preference benchmarks
BenchmarkClaude Fable 5GPT-4.5
LMArena Text14911417
LMArena Creative Writing14941394
EQ-Bench Creative Writing19431258
LMArena Multi-Turn15051444
Short-Story Creative Writing—75.6%
EQ-Bench 41340—
LiveBench Language—61.5%

Frequently asked questions

Is Claude Fable 5 better than GPT-4.5?

Claude Fable 5 is the stronger model overall, scoring 66.3 to 36.9 on the Noometry Index.

Is Claude Fable 5 or GPT-4.5 better for coding?

Claude Fable 5 scores higher on coding benchmarks: 67.0 versus 41.8 in the Noometry coding category.

How many benchmarks do Claude Fable 5 and GPT-4.5 share?

26 benchmarks have published results for both models. Claude Fable 5 has 61 scored results on Noometry and GPT-4.5 has 42.

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