Compare · AI models
GPT-5.5 Pro vs Claude Opus 4.8
RANKED BY EPOCH CAPABILITIES INDEX (ECI)
#5 VS #10
CHECKED 28 SEPT 2026
Side by side
Verdict
GPT-5.5 Pro ranks #5 of 20 on Epoch Capabilities Index (ECI) (162.45); Claude Opus 4.8 ranks #10 (158.30).
Rank 05 of 20 · leads
Epoch Capabilities Index (ECI)
162.45
MakerOpenAI
Date2026
Verified—
Evidence
Epoch AI epoch_capabilities_index/eci_scores.csv (LLM Benchmark Data ZIP, fetched 2026-09-28). ECI 162.45, accessibility API access, release date 2026-04-23. Pricing/context via Statlyte (statlyte.com/models/openai/gpt-5-5-pro), MIT licensed.Rank 10 of 20
Epoch Capabilities Index (ECI)
158.30
MakerAnthropic
Date2026
Verified—
Evidence
Epoch AI epoch_capabilities_index/eci_scores.csv (LLM Benchmark Data ZIP, fetched 2026-09-28). ECI 158.3, accessibility API access, release date 2026-05-28. Pricing/context via Statlyte (statlyte.com/models/anthropic/claude-opus-4-8), MIT licensed.Try another pair
More GPT-5.5 Pro matchups
- GPT-5.5 Pro vs GPT-6 Astra
- GPT-5.5 Pro vs Claude Fable 5.1
- GPT-5.5 Pro vs Claude Fable 5
- GPT-5.5 Pro vs Claude Opus 5
- GPT-5.5 Pro vs GPT-5.6 Sol
- GPT-5.5 Pro vs GPT-5.6 Terra
- GPT-5.5 Pro vs GPT-5.5
- GPT-5.5 Pro vs GPT-5.4 Pro
- GPT-5.5 Pro vs Gemini 3.7 Flash
- GPT-5.5 Pro vs Kimi K3
- GPT-5.5 Pro vs Gemini 3.8 Flash
- GPT-5.5 Pro 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