GPT-4o vs Grok 4.5

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

Grok 4.5

xAI

AI Mastery Index93.4

LMSYS Arena1465

Technical (MMLU-Pro)92.8%

Cost per 1M Tokens$2

Architect's Verdict

When comparing GPT-4o and Grok 4.5, Grok 4.5 edges out in overall capabilities according to the AI Mastery Index. However, for cost-sensitive workloads, Grok 4.5 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.