Noometry

Model comparison

Claude Fable 5.1 vs GPT-4o

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 28.6 on the Noometry Index. GPT-4o costs 4.6× less per token, which makes it the better buy when Claude Fable 5.1's lead doesn't matter for your workload.

Last verified . 31 shared benchmarks.

Claude Fable 5.1 Anthropic

69.0

Rank #2 Confirmed

GPT-4o OpenAI

28.6

Rank #324 Confirmed

Summary

  • They share 31 benchmarks with published results for both. Claude Fable 5.1 scores higher in 10 categories and GPT-4o in 0 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Fable 5.1 leads 89.6 to 10.6.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 100% for Claude Fable 5.1 and 6.4% for GPT-4o.
  • GPT-4o is cheaper at $2.50 / $10 per million input/output tokens, against $10 / $50 for Claude Fable 5.1.
  • Claude Fable 5.1 accepts more context: 1M tokens versus 128K.

Side by side

Claude Fable 5.1GPT-4o
ProviderAnthropicOpenAI
Noometry Index69.028.6
Released2026-09-012024-05-13
WeightsProprietaryProprietary
Context window1M128K
Max output128K16K
Input $ / M tokens$10$2.50
Output $ / M tokens$50$10
Results tracked5272

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Category by category

Coding Claude Fable 5.1 leads

Claude Fable 5.1: 74.7 (#1), GPT-4o: 24.8 (#328)

BenchmarkClaude Fable 5.1GPT-4o
GSO88.2%0%
WeirdML92.9%25.1%
LMArena Coding15281297
SWE-bench Verified—31%
FrontierCode50.9%—
SWE-bench Verified (bash only)—21.6%
Aider Polyglot—45.3%
CursorBench51.8%—
LMArena WebDev1744—
FrontierSWE56.3%—
SciCode63.1%—
BigCodeBench Instruct—51.1%
LiveBench Coding—51.4%
MirrorCode73.3%—
BigCodeBench Complete—61.1%
CadEval—26%
ALE-Bench2,143—
HumanEval+—87.2%
MBPP+—72.2%

Agentic & Tool Use Claude Fable 5.1 leads

Claude Fable 5.1: 50.7 (#5), GPT-4o: 21.0 (#141)

BenchmarkClaude Fable 5.1GPT-4o
APEX-Agents68.6%—
GDPval—9.9%
Remote Labor Index17.9%—
TheAgentCompany—8.6%
Cybench—12.5%
BALROG—32.3%
GDP.pdf29.6%—
LMArena Search—1006
METR Time Horizons—40.8%
Vending-Bench 25,422—

Reasoning Claude Fable 5.1 leads

Claude Fable 5.1: 76.7 (#7), GPT-4o: 9.4 (#343)

BenchmarkClaude Fable 5.1GPT-4o
ARC-AGI-290%0%
ARC-AGI-197.5%4.5%
CritPt31.1%0%
Chess Puzzles47%13%
LMArena Hard Prompts15261281
DTBench97.6%64.5%
LMCA65.5%16.6%
Epoch Capabilities Index164.7128.97
SimpleBench—17.8%
NYT Connections (extended)90%—
EnigmaEval—0.8%
EBR-Bench57.1%—
LiveBench Reasoning—55.8%
Mystery Game Puzzles58%—
LiveBench Data Analysis—60.9%
ForecastBench—57.7
LiveBench—55.3%

Math Claude Fable 5.1 leads

Claude Fable 5.1: 89.6 (#4), GPT-4o: 10.6 (#312)

BenchmarkClaude Fable 5.1GPT-4o
FrontierMath (Tiers 1-3)90.2%0.4%
OTIS Mock AIME 2024-2025100%6.4%
LMArena Math15251285
FrontierMath Tier 487.8%—
ProofBench100%—
Omni-MATH—29.3%
LiveBench Math—49.5%
MATH Level 5—53.3%
FrontierMath (Feb 2025 set)—0.3%
FrontierMath Erdős0%—

Knowledge Claude Fable 5.1 leads

Claude Fable 5.1: 69.6 (#6), GPT-4o: 28.8 (#242)

BenchmarkClaude Fable 5.1GPT-4o
Humanity's Last Exam46.5%2.7%
SimpleQA Verified70.8%26%
LMArena Expert15351250
GPQA Diamond—49.2%
MMLU-Pro—71.3%
Confabulations—15.3%
Vectara Hallucination Rate—9.6%
GPQA (HELM)—52%
MMLU—88.1%

Multimodal Claude Fable 5.1 leads

Claude Fable 5.1: 53.9 (#4), GPT-4o: 34.5 (#91)

BenchmarkClaude Fable 5.1GPT-4o
LMArena Vision13181137
Video-MME—71.9%
GeoBench—71%
VPCT—40%
Blueprint-Bench 241.9%—
Furniture Assembly70%—
LMArena Document1513—
ScienceQA—88.5%

Multilingual Claude Fable 5.1 leads

Claude Fable 5.1: 59.1 (#3), GPT-4o: 43.2 (#186)

BenchmarkClaude Fable 5.1GPT-4o
LMArena Non-English15071283
LMArena Chinese15861277
LMArena French15251304
LMArena German15001282
LMArena Japanese15431257
LMArena Korean15341234
LMArena Russian15211286
LMArena Spanish15161292

Instruction Following Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#6), GPT-4o: 66.6 (#207)

BenchmarkClaude Fable 5.1GPT-4o
LMArena Instruction Following15171278
LiveBench Instruction Following—68.6%
IFEval—81.7%

Long Context Claude Fable 5.1 leads

Claude Fable 5.1: 46.7 (#20), GPT-4o: 39.4 (#179)

BenchmarkClaude Fable 5.1GPT-4o
LMArena Longer Query15221289
Fiction.LiveBench—66.7%

Writing & Preference Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#2), GPT-4o: 52.6 (#166)

BenchmarkClaude Fable 5.1GPT-4o
LMArena Text15101300
LMArena Creative Writing15071292
LMArena Multi-Turn14921302
Short-Story Creative Writing—81.8%
EQ-Bench Creative Writing2162—
WildBench—82.8%
LiveBench Language—47.6%

Frequently asked questions

Is Claude Fable 5.1 better than GPT-4o?

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 28.6 on the Noometry Index. GPT-4o costs 4.6× less per token, which makes it the better buy when Claude Fable 5.1's lead doesn't matter for your workload.

Which is cheaper, Claude Fable 5.1 or GPT-4o?

GPT-4o is cheaper. It lists at $2.50 per million input tokens and $10 per million output tokens; Claude Fable 5.1 lists at $10 and $50.

Is Claude Fable 5.1 or GPT-4o better for coding?

Claude Fable 5.1 scores higher on coding benchmarks: 74.7 versus 24.8 in the Noometry coding category.

Which has the bigger context window?

Claude Fable 5.1 does, with 1M tokens against 128K.

How many benchmarks do Claude Fable 5.1 and GPT-4o share?

31 benchmarks have published results for both models. Claude Fable 5.1 has 52 scored results on Noometry and GPT-4o has 72.

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