Claude Opus 4.8 vs Gemini 3.1 Ultra

Head-to-head technical comparison of intelligence, capabilities, and API pricing.

Claude Opus 4.8

Anthropic

AI Mastery Index94.6

LMSYS Arena1362

Technical (MMLU-Pro)94.5%

Cost per 1M Tokens$15

Gemini 3.1 Ultra

Google

AI Mastery Index92.5

LMSYS Arena1320

Technical (MMLU-Pro)92.5%

Cost per 1M Tokens$20

Architect's Verdict

When comparing Claude Opus 4.8 and Gemini 3.1 Ultra, Claude Opus 4.8 edges out in overall capabilities according to the AI Mastery Index. However, for cost-sensitive workloads, Claude Opus 4.8 offers a more economical API at $15 per 1M tokens. Your choice should depend heavily on whether you prioritize raw reasoning (MMLU) or scalable deployment economics.