GPT-4o vs Gemini 3.1 Ultra

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

GPT-4o

OpenAI

AI Mastery Index87.2

LMSYS Arena1287

Technical (MMLU-Pro)88.7%

Cost per 1M Tokens$5

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 GPT-4o and Gemini 3.1 Ultra, Gemini 3.1 Ultra edges out in overall capabilities according to the AI Mastery Index. However, for cost-sensitive workloads, GPT-4o offers a more economical API at $5 per 1M tokens. Your choice should depend heavily on whether you prioritize raw reasoning (MMLU) or scalable deployment economics.