Claude Sonnet 4.5 vs OpenAI o3

Compare Claude Sonnet 4.5 by Anthropic against OpenAI o3 by OpenAI, in 2 community votes, claude sonnet 4.5 wins 100% of head-to-head duels, tested across 42 shared challenges. Updated February 2026.

In 2 community votes, Claude Sonnet 4.5 wins 100% of head-to-head duels. Based on blind community voting from the RIVAL open dataset of 2+ human preference judgments for this pair.

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