GPT-5.6 Sol vs Claude Sonnet 5

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

GPT-5.6 Sol

OpenAI

AI Mastery Index95.7

LMSYS Arena1485

Technical (MMLU-Pro)95.1%

Cost per 1M Tokens$5

Claude Sonnet 5

Anthropic

AI Mastery Index94.8

LMSYS Arena1472

Technical (MMLU-Pro)94.6%

Cost per 1M Tokens$2

Architect's Verdict

When comparing GPT-5.6 Sol and Claude Sonnet 5, GPT-5.6 Sol 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.