Gemini 3.1 Ultra vs Claude Sonnet 5

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

Gemini 3.1 Ultra

Google

AI Mastery Index92.5

LMSYS Arena1320

Technical (MMLU-Pro)92.5%

Cost per 1M Tokens$20

Claude Sonnet 5

Anthropic

AI Mastery Index94

LMSYS Arena1356

Technical (MMLU-Pro)94%

Cost per 1M Tokens$2

Architect's Verdict

When comparing Gemini 3.1 Ultra and Claude Sonnet 5, Claude Sonnet 5 edges out in overall capabilities according to the AI Mastery Index. However, for cost-sensitive workloads, Claude Sonnet 5 offers a more economical API at $2 per 1M tokens. Your choice should depend heavily on whether you prioritize raw reasoning (MMLU) or scalable deployment economics.