Compare · AI models
Claude Opus 5 vs GPT-5.5
RANKED BY EPOCH CAPABILITIES INDEX (ECI)
#4 VS #8
CHECKED 28 SEPT 2026
Side by side
Verdict
Claude Opus 5 ranks #4 of 20 on Epoch Capabilities Index (ECI) (162.67); GPT-5.5 ranks #8 (159.25).
Rank 04 of 20 · leads
Epoch Capabilities Index (ECI)
162.67
MakerAnthropic
Date2026
Verified—
Evidence
Epoch AI epoch_capabilities_index/eci_scores.csv (LLM Benchmark Data ZIP, fetched 2026-09-28). ECI 162.67, accessibility API access, release date 2026-07-24. Pricing/context via Statlyte (statlyte.com/models/anthropic/claude-opus-5), MIT licensed.Rank 08 of 20
Epoch Capabilities Index (ECI)
159.25
MakerOpenAI
Date2026
Verified—
Evidence
Epoch AI epoch_capabilities_index/eci_scores.csv (LLM Benchmark Data ZIP, fetched 2026-09-28). ECI 159.25, accessibility API access, release date 2026-04-23. Pricing/context via Statlyte (statlyte.com/models/openai/gpt-5-5), MIT licensed.Try another pair
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- Claude Opus 5 vs GPT-5.4 Pro
- Claude Opus 5 vs Claude Opus 4.8
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- Claude Opus 5 vs Kimi K3
- Claude Opus 5 vs Gemini 3.8 Flash
- Claude Opus 5 vs GPT-5.4
Source Ranking: Epoch AI, AI Benchmarking Hub, Epoch Capabilities Index (epoch.ai/data/benchmark_data.zip, CC BY 4.0). Per-entry pricing/context:…
Last checked 28 Sept 2026