Model comparison

Claude Fable 5.1 vs GPT-5 Mini

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 41.8 on the Noometry Index. GPT-5 Mini costs 29× less per token, which makes it the better buy when Claude Fable 5.1's lead doesn't matter for your workload.

Last verified . 37 shared benchmarks.

Claude Fable 5.1 Anthropic

69.0

Rank #2 Confirmed

GPT-5 Mini OpenAI

41.8

Rank #128 Confirmed

Summary

  • They share 37 benchmarks with published results for both. Claude Fable 5.1 scores higher in 10 categories and GPT-5 Mini in 0 categories; 10 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Fable 5.1 leads 76.7 to 23.9.
  • The biggest single-benchmark swing is ProofBench: 100% for Claude Fable 5.1 and 9% for GPT-5 Mini.
  • GPT-5 Mini is cheaper at $0.25 / $2 per million input/output tokens, against $10 / $50 for Claude Fable 5.1.
  • Claude Fable 5.1 accepts more context: 1M tokens versus 400K.

Side by side

Claude Fable 5.1 and GPT-5 Mini specifications
Claude Fable 5.1GPT-5 Mini
ProviderAnthropicOpenAI
Noometry Index69.041.8
Released2026-09-012025-08-07
WeightsProprietaryProprietary
Context window1M400K
Max output128K128K
Input $ / M tokens$10$0.25
Output $ / M tokens$50$2
Results tracked5260

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Category by category

Coding Claude Fable 5.1 leads

Claude Fable 5.1: 74.7 (#1), GPT-5 Mini: 40.1 (#146)

Coding benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
SciCode63.1%39.2%
WeirdML92.9%52.7%
LMArena Coding15281406
ALE-Bench2,143799.77
SWE-bench Verified—64.7%
FrontierCode50.9%—
SWE-bench Verified (bash only)—59.8%
CursorBench51.8%—
LMArena WebDev1744—
SWE-bench Multilingual—39.7%
FrontierSWE56.3%—
GSO88.2%—
MirrorCode73.3%—
AlgoTune—1.38

Agentic & Tool Use Claude Fable 5.1 leads

Claude Fable 5.1: 50.7 (#5), GPT-5 Mini: 31.1 (#70)

Agentic & Tool Use benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
Vending-Bench 25,422-31.18
Terminal-Bench—34.8%
APEX-Agents68.6%—
Berkeley Function Calling Leaderboard—55.5%
Remote Labor Index17.9%—
GDP.pdf29.6%—

Reasoning Claude Fable 5.1 leads

Claude Fable 5.1: 76.7 (#7), GPT-5 Mini: 23.9 (#168)

Reasoning benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
ARC-AGI-290%4.4%
ARC-AGI-197.5%54.3%
CritPt31.1%0%
Chess Puzzles47%30%
LMArena Hard Prompts15261380
Mystery Game Puzzles58%10%
DTBench97.6%80.5%
LMCA65.5%34.2%
Epoch Capabilities Index164.7145.52
Kagi LLM Benchmark—70.3%
NYT Connections (extended)90%—
EnigmaEval—8.2%
EBR-Bench57.1%—
ForecastBench—61

Math Claude Fable 5.1 leads

Claude Fable 5.1: 89.6 (#4), GPT-5 Mini: 46.7 (#69)

Math benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
FrontierMath (Tiers 1-3)90.2%46.7%
FrontierMath Tier 487.8%12.2%
OTIS Mock AIME 2024-2025100%86.7%
ProofBench100%9%
LMArena Math15251378
Omni-MATH—72.2%
MATH Level 5—97.8%
FrontierMath (Feb 2025 set)—27.2%
FrontierMath Erdős0%—
FrontierMath Tier 4 (v1)—6.3%

Knowledge Claude Fable 5.1 leads

Claude Fable 5.1: 69.6 (#6), GPT-5 Mini: 45.6 (#86)

Knowledge benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
Humanity's Last Exam46.5%19.4%
SimpleQA Verified70.8%21.6%
LMArena Expert15351379
GPQA Diamond—75%
MMLU-Pro—83.5%
Confabulations—13.3%
Vectara Hallucination Rate—12.9%
GPQA (HELM)—75.6%

Multimodal Claude Fable 5.1 leads

Claude Fable 5.1: 53.9 (#4), GPT-5 Mini: 35.6 (#85)

Multimodal benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
LMArena Vision13181202
VPCT—40.2%
Blueprint-Bench 241.9%—
Furniture Assembly70%—
LMArena Document1513—

Multilingual Claude Fable 5.1 leads

Claude Fable 5.1: 59.1 (#3), GPT-5 Mini: 48.9 (#137)

Multilingual benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
LMArena Non-English15071363
LMArena Chinese15861385
LMArena French15251386
LMArena German15001366
LMArena Japanese15431341
LMArena Korean15341308
LMArena Russian15211362
LMArena Spanish15161355

Instruction Following Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#6), GPT-5 Mini: 76.2 (#46)

Instruction Following benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
LMArena Instruction Following15171357
IFEval—92.7%

Long Context Claude Fable 5.1 leads

Claude Fable 5.1: 46.7 (#20), GPT-5 Mini: 41.9 (#132)

Long Context benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
LMArena Longer Query15221355
Fiction.LiveBench—69.4%

Writing & Preference Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#2), GPT-5 Mini: 55.2 (#148)

Writing & Preference benchmarks
BenchmarkClaude Fable 5.1GPT-5 Mini
LMArena Text15101373
LMArena Creative Writing15071325
EQ-Bench Creative Writing21621313
LMArena Multi-Turn14921363
Short-Story Creative Writing—83.1%
WildBench—85.5%

Frequently asked questions

Is Claude Fable 5.1 better than GPT-5 Mini?

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 41.8 on the Noometry Index. GPT-5 Mini costs 29× 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-5 Mini?

GPT-5 Mini is cheaper. It lists at $0.25 per million input tokens and $2 per million output tokens; Claude Fable 5.1 lists at $10 and $50.

Is Claude Fable 5.1 or GPT-5 Mini better for coding?

Claude Fable 5.1 scores higher on coding benchmarks: 74.7 versus 40.1 in the Noometry coding category.

Which has the bigger context window?

Claude Fable 5.1 does, with 1M tokens against 400K.

How many benchmarks do Claude Fable 5.1 and GPT-5 Mini share?

37 benchmarks have published results for both models. Claude Fable 5.1 has 52 scored results on Noometry and GPT-5 Mini has 60.

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