Epoch Capabilities Index what it measures, how it is scored and who leads it

Name: Epoch Capabilities Index
Creator: Epoch AI

Composite indexes · Epoch AI · ECI

Scores from Epoch Capabilities Index, published Sep 26, 2026

Rank	Model	ECI
1	GPT-6 AstraOpenAI · as “GPT-6 Astra”	166.6
2	Claude Fable 5.1Anthropic · as “Claude Fable 5.1”	165.0
3	Claude Fable 5Anthropic · as “Claude Fable 5”	163.6
4	Claude Opus 5Anthropic · as “Claude Opus 5”	162.7
5	GPT-5.5 ProOpenAI · as “GPT-5.5 Pro”	162.4
6	GPT-5.6 SolOpenAI · as “GPT-5.6 Sol”	162.0
7	GPT-5.6 TerraOpenAI · as “GPT-5.6 Terra”	159.3
8	GPT-5.5OpenAI · as “GPT-5.5”	159.3
9	GPT-5.4 ProOpenAI · as “GPT-5.4 Pro”	159.1
10	Claude Opus 4.8Anthropic · as “Claude Opus 4.8”	158.3
11	Gemini 3.7 FlashGoogle · as “Gemini 3.7 Flash”	157.7
12	Kimi K3Moonshot AI · as “Kimi K3”	157.7
13	Gemini 3.8 FlashGoogle · as “Gemini 3.8 Flash”	157.1
14	GPT-5.4OpenAI · as “GPT-5.4”	156.9
15	Muse Spark 1.3Meta · as “Muse Spark 1.3”	156.9
16	GPT-5.3 CodexOpenAI · as “GPT-5.3 Codex”	156.8
17	Qwen3.8 Max (0902)Alibaba · as “Qwen 3.8 Max”	156.7
18	Grok 4.6SpaceXAI · as “Grok 4.6”	156.5
19	Claude Opus 4.7Anthropic · as “Claude Opus 4.7”	156.4
20	Claude Sonnet 5Anthropic · as “Claude Sonnet 5”	156.3
21	GPT-5.6 LunaOpenAI · as “GPT-5.6 Luna”	156.3
22	GLM-5.3Z.ai · as “GLM-5.3”	155.6
23	GPT-5.2 ProOpenAI · as “GPT-5.2 Pro”	155.4
24	DeepSeek V4 Pro 0813DeepSeek · as “DeepSeek V4 Pro 0813”	155.4
25	Claude Opus 4.6Anthropic · as “Claude Opus 4.6”	155.4

Sources: each benchmark's paper (arXiv) and its official site or leaderboard. Scores are the boards captured here every day, exactly as published.