Claude Sonnet 5.5 vs Claude Fable 5.1: Release Comparison

Name: Intelligence
Creator: Artificial Analysis
License: https://artificialanalysis.ai/docs/legal/Terms-of-Use.pdf

Comparison of the Claude Sonnet 5.5 and Claude Fable 5.1 releases: 5 and 5 models respectively, each with different intelligence, performance, and pricing characteristics. Below is a comparison of the key metrics across all 10 models.

For intelligence, Claude Sonnet 5.5 scores highest: Claude Sonnet 5.5 (Max, Default Fallback) at 55, against Claude Fable 5.1 (Xhigh, Default Fallback) at 50 for Claude Fable 5.1.
For time per task, Claude Sonnet 5.5 is fastest: Claude Sonnet 5.5 (Low, Default Fallback) at 2.7 min, against Claude Fable 5.1 (Low, Default Fallback) at 7.2 min for Claude Fable 5.1.
For cost per task, Claude Sonnet 5.5 is cheapest: Claude Sonnet 5.5 (Low, Default Fallback) at $0.51, against Claude Fable 5.1 (Low, Default Fallback) at $4.47 for Claude Fable 5.1.

Model Playground

Releases compared


	Claude Sonnet 5.5 (max)	Claude Fable 5.1 (xhigh)	Claude Sonnet 5.5 (xhigh)	Claude Fable 5.1 (max)	Claude Fable 5.1 (high)	Claude Fable 5.1 (medium)	Claude Sonnet 5.5 (high)	Claude Fable 5.1 (low)	Claude Sonnet 5.5 (medium)	Claude Sonnet 5.5 (low)
Intelligence Index	55	50	50	49	47	43	42	39	31	26
Finance & Accounting	56	54	49	54	50	47	44	48	41	36
Strategy & Ops	58	56	54	58	54	52	51	51	47	42
Legal	52	54	47	54	50	48	44	47	39	37
Healthcare & Medical	54	51	47	51	48	45	44	44	40	37
Engineering	58	57	54	57	54	50	46	46	37	33
Economics	54	56	48	57	52	50	45	48	39	35
AA-Briefcase v1.1	1813	1649	1742	1669	1577	1525	1634	1478	1439	1268
AutomationBench-AA	71.8%	57.8%	65.5%	59.4%	55.3%	54.7%	59.4%	52.2%	54.9%	49.4%
Terminal-Bench 4.0	63.6%	55.1%	57.1%	52.0%	52.0%	44.9%	43.9%	40.4%	29.8%	20.7%
FrontierCode 2.0	41.7%	35.7%	35.6%	31.6%	30.3%	28.8%	25.7%	22.8%	11.0%	7.1%
AA-Omniscience v1.1	30	44	21	46	40	36	19	34	19	20
GDP.pdf	25.8%	26.2%	24.6%	26.2%	26.8%	26.8%	25.2%	28.0%	20.2%	16.0%
HLE-Diamond	53.3%	58.8%	44.1%	60.1%	50.4%	45.0%	33.8%	37.4%	23.8%	20.6%
CritPt v2 (Hard Subset)	59.0%	60.0%	57.5%	52.5%	62.0%	58.5%	51.5%	49.5%	33.5%	26.0%
Terminal-Bench-Science 0.1	53.3%	40.5%	52.4%	43.3%	39.5%	29.0%	34.3%	21.4%	16.2%	10.5%

Cost per TaskUSD	$10.02	$10.85	$4.09	$12.99	$7.54	$5.56	$1.64	$4.47	$0.78	$0.51
Input PriceUSD/1M Tokens	$2.00	$10.00	$2.00	$10.00	$10.00	$10.00	$2.00	$10.00	$2.00	$2.00
Output PriceUSD/1M Tokens	$10.00	$50.00	$10.00	$50.00	$50.00	$50.00	$10.00	$50.00	$10.00	$10.00
Cache Hit PriceUSD/1M Tokens	$0.10	$0.25	$0.10	$0.25	$0.25	$0.25	$0.10	$0.25	$0.10	$0.10
Cache Write PriceUSD/1M Tokens	$2.50	$12.50	$2.50	$12.50	$12.50	$12.50	$2.50	$12.50	$2.50	$2.50

Time per TaskMinutes	31.1	18.5	15.2	22.6	12.7	9.3	7.0	7.2	3.6	2.7
Output Speedtok/s	153	88	134	87	87	87	139	87	143	131
Time to First Answer Tokens	303.84	68.40	32.09	195.76	17.85	10.74	11.75	7.06	5.40	3.28
Time to First Tokens	303.84	68.40	32.09	195.76	17.85	10.74	11.75	7.06	5.40	3.28
End-to-End TimeMean of Single-Request Workloads (s)	604.99	217.01	93.83	450.51	99.18	84.98	52.69	72.81	31.82	26.90

Context Window	1M	1M	1M	1M	1M	1M	1M	1M	1M	1M
Creator	Anthropic	Anthropic	Anthropic	Anthropic	Anthropic	Anthropic	Anthropic	Anthropic	Anthropic	Anthropic
License	Proprietary	Proprietary	Proprietary	Proprietary	Proprietary	Proprietary	Proprietary	Proprietary	Proprietary	Proprietary
Input Modality	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text and image	Supports: text and image
Output Modality	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text	Supports: text
Providers

Updated

Intelligence

Artificial Analysis Intelligence Index · Higher is better

Time per Task

Inference time (minutes) per Intelligence Index task · Lower is better

Cost per Task

Weighted average cost (USD) per Intelligence Index task · Lower is better

IntelligenceUpdated

Artificial Analysis Intelligence Index

Artificial Analysis Intelligence Index v5.0.1 incorporates 9 evaluations: AA-Briefcase v1.1, AutomationBench-AA, Terminal-Bench 4.0, FrontierCode 2.0, AA-Omniscience v1.1, GDP.pdf, HLE-Diamond, CritPt v2 (Hard Subset), and Terminal-Bench-Science 0.1

No publicly available API

Artificial Analysis Intelligence Index v5.0.1 includes: AA-Briefcase v1.1, AutomationBench-AA, Terminal-Bench 4.0, FrontierCode 2.0, AA-Omniscience v1.1, GDP.pdf, HLE-Diamond, CritPt v2 (Hard Subset), Terminal-Bench-Science 0.1. See Intelligence Index methodology for further details, including a breakdown of each evaluation and how we run them.

Intelligence Index vs. Cost per Task

Artificial Analysis Intelligence Index · Weighted average cost (USD) per Artificial Analysis Intelligence Index task

Most attractive quadrant

Claude Sonnet 5.5

Claude Fable 5.1

Pareto line

AA-Briefcase v1.1

AutomationBench-AA

Cost per Task (USD, Log Scale)

Weighted average cost per Intelligence Index task. Each evaluation’s cost is calculated from input, cache hit, cache write, reasoning, and answer token prices, divided by task count, and weighted by its Intelligence Index weight.

Cost

Cost per Intelligence Index Task

Weighted average cost (USD) per Intelligence Index task · Segmented by token type · Lower is better

No publicly available API

Speed & Latency

Time per Intelligence Index Task

Output tokens divided by end-to-end output speed (minutes per Intelligence Index task) · Speed at the model's own endpoint or the median across providers · Lower is better

No publicly available API

The weighted average time (minutes) per Artificial Analysis Intelligence Index task: output tokens per task divided by output speed, weighted by each benchmark's weight in the Intelligence Index.

Speed and latency metrics average each endpoint's runs over the past 5 days, and the error rate pools them. We run the benchmark every 6 hours, and endpoints of deprecated models every 18 hours.

Capability Scores

Capability Indexes

Measures the performance of models on specific capabilities and industries

Finance & Accounting Index

Incorporates 5 evaluations: AA-Briefcase v1.1, AA-Omniscience v1.1, HLE-Diamond, AutomationBench-AA, GDP.pdf · Higher is better

Strategy & Ops Index

Incorporates 4 evaluations: AutomationBench-AA, AA-Briefcase v1.1, AA-Omniscience v1.1, GDP.pdf · Higher is better

Legal Index

Incorporates 5 evaluations: AA-Omniscience v1.1, AA-Briefcase v1.1, HLE-Diamond, GDP.pdf, AutomationBench-AA · Higher is better

Healthcare & Medical Index

Incorporates 5 evaluations: AA-Omniscience v1.1, AA-Briefcase v1.1, MLCR-AA, AutomationBench-AA, HLE-Diamond · Higher is better

Engineering Index

Incorporates 7 evaluations: AA-Omniscience v1.1, CritPt v2 (Hard Subset), Terminal-Bench-Science 0.1, HLE-Diamond, Terminal-Bench 4.0, FrontierCode 2.0, AA-Briefcase v1.1 · Higher is better

Economics Index

Incorporates 4 evaluations: AA-Omniscience v1.1, AA-Briefcase v1.1, HLE-Diamond, GDP.pdf · Higher is better

Benchmarks

AA-PersonalityBenchNew

Model AvsModel B

AA-PersonalityBench: Expressiveness Index, Claude Sonnet 5.5 (max) vs Claude Fable 5.1 (max)

Chance each model’s answer is judged to show more of each trait from their Elo gap · 50% is an even match

Claude Sonnet 5.5 (max)

Claude Fable 5.1 (max)

Eloquent

97%

Natural Sounding

96%

Lexically Varied

94%

Metaphorical

27%

73%

Literate

41%

59%

Claude Sonnet 5.5 vs Claude Fable 5.1: Release Comparison

Intelligence

Time per Task

Cost per Task

IntelligenceUpdated

Artificial Analysis Intelligence Index

Artificial Analysis Intelligence Index

Intelligence Index vs. Cost per Task

Cost per Intelligence Index Task

Artificial Analysis Intelligence Index

Cost

Cost per Intelligence Index Task

Cost per Intelligence Index Task

Speed & Latency

Time per Intelligence Index Task

Time per Intelligence Index Task

Time Period

Capability Scores

Capability Indexes

Benchmarks

AA-PersonalityBenchNew

AA-PersonalityBench: Expressiveness Index, Claude Sonnet 5.5 (max) vs Claude Fable 5.1 (max)