Compare · ModelsLive · 2 picked · head to head

Claude Fable 5.1 vs Claude Sonnet 5.5

Side by side · benchmarks, pricing, and signals you can act on.

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Winner summary

Claude Sonnet 5.5 wins on 8/16 benchmarks

Claude Sonnet 5.5 wins 8 of 16 shared benchmarks. Leads in speed · agentic · coding.

Category leads

speed·Claude Sonnet 5.5agentic·Claude Sonnet 5.5coding·Claude Sonnet 5.5math·Claude Fable 5.1general·Claude Sonnet 5.5knowledge·Claude Fable 5.1

Hype vs Reality

Attention vs performance

Claude Fable 5.1

#16 by perf·#12 by attention

UNDERRATED

Claude Sonnet 5.5

#11 by perf·#10 by attention

DESERVED

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Best value

Claude Sonnet 5.5

5.3x better value than Claude Fable 5.1

Claude Fable 5.1

2.4 pts/$

$30.00/M

Claude Sonnet 5.5

12.5 pts/$

$6.00/M

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Vendor risk

Who is behind the model

Anthropic

$965.0B·Tier 1

Medium risk

Anthropic

$965.0B·Tier 1

Medium risk

See the AI economy →

Head to head

16 benchmarks · 2 models

Claude Fable 5.1Claude Sonnet 5.5

Artificial Analysis · CritPt

Claude Sonnet 5.5 leads by +1.7

Claude Fable 5.1

29.7

Claude Sonnet 5.5

31.4

Artificial Analysis · GDPval

Claude Sonnet 5.5 leads by +5.3

Claude Fable 5.1

61.7

Claude Sonnet 5.5

67.0

Artificial Analysis · Humanity's Last Exam

Claude Fable 5.1 leads by +4.1

Claude Fable 5.1

59.1

Claude Sonnet 5.5

55.0

Artificial Analysis · Long Context Reasoning

Claude Fable 5.1 leads by +2.6

Claude Fable 5.1

85.3

Claude Sonnet 5.5

82.7

Artificial Analysis · Quality Index

Claude Sonnet 5.5 leads by +2.6

Claude Fable 5.1

53.4

Claude Sonnet 5.5

56.0

Artificial Analysis · SciCode

Claude Fable 5.1 leads by +2.1

Claude Fable 5.1

63.1

Claude Sonnet 5.5

61.0

APEX-Agents

Claude Sonnet 5.5 leads by +6.9

APEX-Agents · evaluates AI agents on complex, multi-step tasks requiring planning, tool use, and autonomous decision-making in realistic environments.

Claude Fable 5.1

68.6

Claude Sonnet 5.5

75.5

Frontiercode

Claude Sonnet 5.5 leads by +1.2

Claude Fable 5.1

50.9

Claude Sonnet 5.5

52.1

FrontierMath-Tier-4-v2-Private

Claude Fable 5.1 leads by +7.3

Claude Fable 5.1

87.8

Claude Sonnet 5.5

80.5

FrontierMath-Tiers-1-3-v2-Private

Claude Fable 5.1 leads by +1.4

Claude Fable 5.1

90.2

Claude Sonnet 5.5

88.8

Frontierswe

Claude Sonnet 5.5 leads by +5.6

Claude Fable 5.1

56.3

Claude Sonnet 5.5

61.9

Furniture Assembly

Claude Sonnet 5.5 leads by +7.2

Claude Fable 5.1

57.1

Claude Sonnet 5.5

64.3

Mystery Game Puzzles

Claude Sonnet 5.5 leads by +7.7

Claude Fable 5.1

53.7

Claude Sonnet 5.5

61.5

OTIS Mock AIME 2024-2025

OTIS Mock AIME 2024-2025 · simulated American Invitational Mathematics Examination problems testing advanced problem-solving skills.

Claude Fable 5.1

100.0

Claude Sonnet 5.5

100.0

Proofbench

Claude Fable 5.1

100.0

Claude Sonnet 5.5

100.0

SimpleQA Verified

Claude Fable 5.1 leads by +24.3

SimpleQA Verified · short factual questions with verified answers, measuring factual accuracy and the tendency to hallucinate or provide incorrect information.

Claude Fable 5.1

70.8

Claude Sonnet 5.5

46.5

Full benchmark table

Benchmark	Claude Fable 5.1	Claude Sonnet 5.5
Artificial Analysis · CritPt	29.7	31.4
Artificial Analysis · GDPval	61.7	67.0
Artificial Analysis · Humanity's Last Exam	59.1	55.0
Artificial Analysis · Long Context Reasoning	85.3	82.7
Artificial Analysis · Quality Index	53.4	56.0
Artificial Analysis · SciCode	63.1	61.0
APEX-Agents APEX-Agents · evaluates AI agents on complex, multi-step tasks requiring planning, tool use, and autonomous decision-making in realistic environments.	68.6	75.5
Frontiercode	50.9	52.1
FrontierMath-Tier-4-v2-Private	87.8	80.5
FrontierMath-Tiers-1-3-v2-Private	90.2	88.8
Frontierswe	56.3	61.9
Furniture Assembly	57.1	64.3
Mystery Game Puzzles	53.7	61.5
OTIS Mock AIME 2024-2025 OTIS Mock AIME 2024-2025 · simulated American Invitational Mathematics Examination problems testing advanced problem-solving skills.	100.0	100.0
Proofbench	100.0	100.0
SimpleQA Verified SimpleQA Verified · short factual questions with verified answers, measuring factual accuracy and the tendency to hallucinate or provide incorrect information.	70.8	46.5

Pricing · per 1M tokens · projected $/mo at 10M tokens

Model	Input	Output	Context	Projected $/mo
Claude Fable 5.1	$10.00	$50.00	1.0M tokens (~500 books)	$200.00
Claude Sonnet 5.5	$2.00	$10.00	1.0M tokens (~500 books)	$40.00

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