Compare · ModelsLive · 2 picked · head to head

Claude Sonnet 5.5 vs Claude Fable 5.1

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

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Winner summary

Claude Sonnet 5.5 wins on 10/16 benchmarks

Claude Sonnet 5.5 wins 10 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 Sonnet 5.5

#11 by perf·#10 by attention

DESERVED

Claude Fable 5.1

#16 by perf·#12 by attention

UNDERRATED

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Best value

Claude Sonnet 5.5

5.3x better value than Claude Fable 5.1

Claude Sonnet 5.5

12.5 pts/$

$6.00/M

Claude Fable 5.1

2.4 pts/$

$30.00/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 Sonnet 5.5Claude Fable 5.1

Artificial Analysis · CritPt

Claude Sonnet 5.5 leads by +1.7

Claude Sonnet 5.5

31.4

Claude Fable 5.1

29.7

Artificial Analysis · GDPval

Claude Sonnet 5.5 leads by +5.3

Claude Sonnet 5.5

67.0

Claude Fable 5.1

61.7

Artificial Analysis · Humanity's Last Exam

Claude Fable 5.1 leads by +4.1

Claude Sonnet 5.5

55.0

Claude Fable 5.1

59.1

Artificial Analysis · Long Context Reasoning

Claude Fable 5.1 leads by +2.6

Claude Sonnet 5.5

82.7

Claude Fable 5.1

85.3

Artificial Analysis · Quality Index

Claude Sonnet 5.5 leads by +2.6

Claude Sonnet 5.5

56.0

Claude Fable 5.1

53.4

Artificial Analysis · SciCode

Claude Fable 5.1 leads by +2.1

Claude Sonnet 5.5

61.0

Claude Fable 5.1

63.1

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 Sonnet 5.5

75.5

Claude Fable 5.1

68.6

Frontiercode

Claude Sonnet 5.5 leads by +1.2

Claude Sonnet 5.5

52.1

Claude Fable 5.1

50.9

FrontierMath-Tier-4-v2-Private

Claude Fable 5.1 leads by +7.3

Claude Sonnet 5.5

80.5

Claude Fable 5.1

87.8

FrontierMath-Tiers-1-3-v2-Private

Claude Fable 5.1 leads by +1.4

Claude Sonnet 5.5

88.8

Claude Fable 5.1

90.2

Frontierswe

Claude Sonnet 5.5 leads by +5.6

Claude Sonnet 5.5

61.9

Claude Fable 5.1

56.3

Furniture Assembly

Claude Sonnet 5.5 leads by +7.2

Claude Sonnet 5.5

64.3

Claude Fable 5.1

57.1

Mystery Game Puzzles

Claude Sonnet 5.5 leads by +7.7

Claude Sonnet 5.5

61.5

Claude Fable 5.1

53.7

OTIS Mock AIME 2024-2025

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

Claude Sonnet 5.5

100.0

Claude Fable 5.1

100.0

Proofbench

Claude Sonnet 5.5

100.0

Claude Fable 5.1

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 Sonnet 5.5

46.5

Claude Fable 5.1

70.8

Full benchmark table

Benchmark	Claude Sonnet 5.5	Claude Fable 5.1
Artificial Analysis · CritPt	31.4	29.7
Artificial Analysis · GDPval	67.0	61.7
Artificial Analysis · Humanity's Last Exam	55.0	59.1
Artificial Analysis · Long Context Reasoning	82.7	85.3
Artificial Analysis · Quality Index	56.0	53.4
Artificial Analysis · SciCode	61.0	63.1
APEX-Agents APEX-Agents · evaluates AI agents on complex, multi-step tasks requiring planning, tool use, and autonomous decision-making in realistic environments.	75.5	68.6
Frontiercode	52.1	50.9
FrontierMath-Tier-4-v2-Private	80.5	87.8
FrontierMath-Tiers-1-3-v2-Private	88.8	90.2
Frontierswe	61.9	56.3
Furniture Assembly	64.3	57.1
Mystery Game Puzzles	61.5	53.7
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.	46.5	70.8

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

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

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