Gemini 3.1 Ultra vs Gemini 1.5 Pro

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

Gemini 1.5 Pro

Google

AI Mastery Index86.4

LMSYS Arena1265

Technical (MMLU-Pro)85.9%

Cost per 1M Tokens$3.5

Architect's Verdict

When comparing Gemini 3.1 Ultra and Gemini 1.5 Pro, Gemini 3.1 Ultra edges out in overall capabilities according to the AI Mastery Index. However, for cost-sensitive workloads, Gemini 1.5 Pro offers a more economical API at $3.5 per 1M tokens. Your choice should depend heavily on whether you prioritize raw reasoning (MMLU) or scalable deployment economics.