Model comparison

Claude Fable 5 vs GPT-5.4 mini

Claude Fable 5 is the stronger model overall, scoring 66.8 to 45.0 on the Noometry Index. GPT-5.4 mini costs 12× less per token, which makes it the better buy when Claude Fable 5's lead doesn't matter for your workload.

Last verified . 40 shared benchmarks.

Claude Fable 5 Anthropic

66.8

Rank #5 Confirmed

GPT-5.4 mini OpenAI

45.0

Rank #76 Confirmed

Summary

  • They share 40 benchmarks with published results for both. Claude Fable 5 scores higher in 10 categories and GPT-5.4 mini in 0 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Fable 5 leads 76.8 to 30.4.
  • The biggest single-benchmark swing is FrontierMath Tier 4: 90.2% for Claude Fable 5 and 9.8% for GPT-5.4 mini.
  • GPT-5.4 mini is cheaper at $0.75 / $4.50 per million input/output tokens, against $10 / $50 for Claude Fable 5.
  • Claude Fable 5 accepts more context: 1M tokens versus 400K.

Side by side

Claude Fable 5 and GPT-5.4 mini specifications
Claude Fable 5GPT-5.4 mini
ProviderAnthropicOpenAI
Noometry Index66.845.0
Released2026-06-072026-03-17
WeightsProprietaryProprietary
Context window1M400K
Max output128K128K
Input $ / M tokens$10$0.75
Output $ / M tokens$50$4.50
Results tracked6246

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Category by category

Coding Claude Fable 5 leads

Claude Fable 5: 70.6 (#4), GPT-5.4 mini: 45.2 (#72)

Coding benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
FrontierCode53.5%27%
LMArena WebDev16251397
SciCode61%49.9%
WeirdML91.9%60.3%
LMArena Coding15191438
ALE-Bench2,0411,189
DeepSWE69.9%—
FrontierSWE47%—
GSO78.4%—
MirrorCode63.9%—

Agentic & Tool Use Claude Fable 5 leads

Claude Fable 5: 54.0 (#2), GPT-5.4 mini: 29.9 (#81)

Agentic & Tool Use benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
APEX-Agents63.6%—
Remote Labor Index16.1%—
τ²-bench Banking39.7%—
DeepResearch Bench—36.3%
PostTrainBench41.8%—
GBAEval74.5%—
GDP.pdf30%—
LMArena Search1230—
Vending-Bench 25,680—

Reasoning Claude Fable 5 leads

Claude Fable 5: 76.8 (#6), GPT-5.4 mini: 30.4 (#85)

Reasoning benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
ARC-AGI-289.2%18.9%
Kagi LLM Benchmark91.4%37.9%
NYT Connections (extended)92.7%61.8%
ARC-AGI-198.5%63.7%
CritPt28.6%10%
Chess Puzzles41%24%
LMArena Hard Prompts15081424
Mystery Game Puzzles52%11%
DTBench98.4%80%
LMCA61.1%40.8%
Epoch Capabilities Index162.06148.84
SimpleBench81.9%—
EnigmaEval39.3%—
Thematic Generalization—61.7%
EBR-Bench39.5%—
Surface Evolver Bench95%—
Bench to the Future 30.13—
ForecastBench—57

Math Claude Fable 5 leads

Claude Fable 5: 88.5 (#5), GPT-5.4 mini: 45.5 (#75)

Math benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
FrontierMath (Tiers 1-3)87%51.2%
FrontierMath Tier 490.2%9.8%
OTIS Mock AIME 2024-2025100%88.9%
ProofBench95%21%
LMArena Math15191419
FrontierMath (Feb 2025 set)—28.3%
FrontierMath Erdős0%—
FrontierMath Tier 4 (v1)—2.1%

Knowledge Claude Fable 5 leads

Claude Fable 5: 62.2 (#25), GPT-5.4 mini: 51.5 (#67)

Knowledge benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
GPQA Diamond85.9%86.9%
SimpleQA Verified70.7%29.4%
LMArena Expert15341435
Vectara Hallucination Rate—5.5%

Multimodal Claude Fable 5 leads

Claude Fable 5: 45.3 (#17), GPT-5.4 mini: 39.7 (#56)

Multimodal benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
LMArena Vision13241245
Blueprint-Bench 238.6%—
Furniture Assembly35.8%—
LMArena Document1496—

Multilingual Claude Fable 5 leads

Claude Fable 5: 57.3 (#9), GPT-5.4 mini: 51.9 (#96)

Multilingual benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
LMArena Non-English14811405
LMArena Chinese15431446
LMArena French15051440
LMArena German14861409
LMArena Japanese15061374
LMArena Korean14881368
LMArena Russian15041417
LMArena Spanish14981405

Instruction Following Claude Fable 5 leads

Claude Fable 5: 78.6 (#8), GPT-5.4 mini: 74.1 (#102)

Instruction Following benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
LMArena Instruction Following15021405

Long Context Claude Fable 5 leads

Claude Fable 5: 46.3 (#23), GPT-5.4 mini: 43.0 (#112)

Long Context benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
LMArena Longer Query15091407

Writing & Preference Claude Fable 5 leads

Claude Fable 5: 75.9 (#5), GPT-5.4 mini: 64.0 (#58)

Writing & Preference benchmarks
BenchmarkClaude Fable 5GPT-5.4 mini
LMArena Text14911412
LMArena Creative Writing14941370
EQ-Bench Creative Writing19431665
LMArena Multi-Turn15041429
EQ-Bench 41340—

Frequently asked questions

Is Claude Fable 5 better than GPT-5.4 mini?

Claude Fable 5 is the stronger model overall, scoring 66.8 to 45.0 on the Noometry Index. GPT-5.4 mini costs 12× less per token, which makes it the better buy when Claude Fable 5's lead doesn't matter for your workload.

Which is cheaper, Claude Fable 5 or GPT-5.4 mini?

GPT-5.4 mini is cheaper. It lists at $0.75 per million input tokens and $4.50 per million output tokens; Claude Fable 5 lists at $10 and $50.

Is Claude Fable 5 or GPT-5.4 mini better for coding?

Claude Fable 5 scores higher on coding benchmarks: 70.6 versus 45.2 in the Noometry coding category.

Which has the bigger context window?

Claude Fable 5 does, with 1M tokens against 400K.

How many benchmarks do Claude Fable 5 and GPT-5.4 mini share?

40 benchmarks have published results for both models. Claude Fable 5 has 62 scored results on Noometry and GPT-5.4 mini has 46.

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