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 56, against Claude Fable 5.1 (Max, Default Fallback) at 53 for Claude Fable 5.1.
For output speed, Claude Sonnet 5.5 is fastest: Claude Sonnet 5.5 (Max, Default Fallback) at 136 t/s, against Claude Fable 5.1 (Max, Default Fallback) at 68 t/s for Claude Fable 5.1.
For cost per task, Claude Sonnet 5.5 is cheapest: Claude Sonnet 5.5 (Low, Default Fallback) at $0.35, against Claude Fable 5.1 (Low, Default Fallback) at $2.37 for Claude Fable 5.1.

Model Playground

Releases compared


	Claude Sonnet 5.5 (max with fallback)	Claude Fable 5.1 (max with fallback)	Claude Fable 5.1 (xhigh with fallback)	Claude Sonnet 5.5 (xhigh with fallback)	Claude Fable 5.1 (high with fallback)	Claude Fable 5.1 (medium with fallback)	Claude Fable 5.1 (low with fallback)	Claude Sonnet 5.5 (high with fallback)	Claude Sonnet 5.5 (medium with fallback)	Claude Sonnet 5.5 (low with fallback)
Intelligence Index	56	53	53	52	51	49	47	47	41	36
Finance & Accounting	57	56	56	52	54	51	49	47	41	38
Strategy & Ops	60	60	58	56	56	54	51	52	45	41
Legal	56	60	61	52	58	57	53	49	44	41
Healthcare & Medical	58	58	--	--	--	--	--	--	--	--
Engineering	58	56	57	54	54	51	49	48	42	38
Economics	61	63	62	56	60	58	55	52	47	44
AA-Briefcase v1.1	1817	1672	1655	1751	1580	1528	1482	1636	1441	1272
GDPval-AA v2.1	1838	1754	1732	1728	1635	1545	1469	1549	1323	1175
AutomationBench-AA	71.8%	59.4%	57.8%	65.5%	55.3%	54.7%	52.2%	59.4%	54.9%	49.4%
Terminal-Bench 4.0	63.6%	52.0%	55.1%	57.1%	52.0%	44.9%	40.4%	43.9%	29.8%	20.7%
SciCode	61.0%	63.1%	60.9%	57.3%	58.7%	56.4%	56.7%	53.7%	52.9%	49.1%
Humanity's Last Exam	55.0%	59.1%	58.7%	50.0%	55.9%	53.8%	48.9%	45.8%	39.8%	36.2%
GDP.pdf	25.8%	26.2%	26.2%	24.6%	26.8%	26.8%	28.0%	25.2%	20.2%	16.0%
CritPt	31.4%	29.7%	31.1%	31.1%	30.3%	29.1%	27.7%	24.6%	16.9%	11.4%
AA-Omniscience	32	43	42	24	41	38	34	21	20	19
AA-LCR v1.1	82.7%	85.3%	83.0%	79.7%	83.7%	84.7%	82.3%	78.0%	76.3%	76.0%

Cost per TaskUSD	$5.46	$7.63	$5.98	$2.01	$3.91	$2.98	$2.37	$0.88	$0.48	$0.35
Input PriceUSD/1M Tokens	$2.00	$10.00	$10.00	$2.00	$10.00	$10.00	$10.00	$2.00	$2.00	$2.00
Output PriceUSD/1M Tokens	$10.00	$50.00	$50.00	$10.00	$50.00	$50.00	$50.00	$10.00	$10.00	$10.00
Cache Hit PriceUSD/1M Tokens	$0.10	$0.25	$0.25	$0.10	$0.25	$0.25	$0.25	$0.10	$0.10	$0.10
Cache Write PriceUSD/1M Tokens	$2.50	$12.50	$12.50	$2.50	$12.50	$12.50	$12.50	$2.50	$2.50	$2.50

Output SpeedTokens/s	136	68	64	112	58	58	58	110	109	109
Time to First Tokens	391.60	141.57	66.71	36.17	19.45	14.26	2.19	11.62	1.11	0.96
Time to First Answer Tokens	391.60	141.57	66.71	36.17	19.45	14.26	2.19	11.62	1.11	0.96
End-to-End Response Times	395.28	148.90	74.56	40.64	28.10	22.95	10.74	16.17	5.70	5.55
Time per Tasks	892.98	737.89	602.72	423.96	406.22	300.46	235.20	218.05	126.27	84.16

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

Intelligence

Artificial Analysis Intelligence Index · Higher is better

Speed

Output tokens per second · Higher is better

Cost per Task

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

Intelligence

Artificial Analysis Intelligence Index

Artificial Analysis Intelligence Index v4.3.2 incorporates 10 evaluations: AA-Briefcase v1.1, GDPval-AA v2.1, AutomationBench-AA, Terminal-Bench 4.0, SciCode, Humanity's Last Exam, GDP.pdf, CritPt, AA-Omniscience, AA-LCR v1.1

Artificial Analysis Intelligence Index v4.3.2 includes: AA-Briefcase v1.1, GDPval-AA v2.1, AutomationBench-AA, Terminal-Bench 4.0, SciCode, Humanity's Last Exam, GDP.pdf, CritPt, AA-Omniscience, AA-LCR v1.1. 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

GDPval-AA v2.1

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

Speed & Latency

Output Speed

Output tokens per second · Higher is better

Tokens per second received while the model is generating tokens (ie. after first chunk has been received from the API for models which support streaming).

Figures represent performance of the model's first-party API or the median across providers where a first-party API is not available.

Capability Scores

Capability Indexes

Measures the performance of models on specific capabilities and industries

Finance & Accounting Index

Incorporates 7 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, Humanity's Last Exam, AutomationBench-AA, AA-LCR v1.1, GDP.pdf · Higher is better

Strategy & Ops Index

Incorporates 6 evaluations: GDPval-AA v2.1, AA-Briefcase v1.1, AA-Omniscience, AutomationBench-AA, AA-LCR v1.1, GDP.pdf · Higher is better

Legal Index

Incorporates 7 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, Humanity's Last Exam, AA-LCR v1.1, GDP.pdf, AutomationBench-AA · Higher is better

Healthcare & Medical Index

Incorporates 6 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, MLCR-AA, Humanity's Last Exam, AutomationBench-AA · Higher is better

Engineering Index

Incorporates 6 evaluations: AA-Omniscience, Humanity's Last Exam, CritPt, GDPval-AA v2.1, AA-Briefcase v1.1, Terminal-Bench 4.0 · Higher is better

Economics Index

Incorporates 5 evaluations: AA-Omniscience, Humanity's Last Exam, GDPval-AA v2.1, AA-Briefcase v1.1, AA-LCR v1.1 · Higher is better

Claude Sonnet 5.5 vs Claude Fable 5.1: Release Comparison

Intelligence

Speed

Cost per Task

Intelligence

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

Output Speed

Output Speed

Model Performance Representation

Capability Scores

Capability Indexes