Claude Sonnet 4.5 vs GPT-5.1-Codex
Compare Claude Sonnet 4.5 by Anthropic against GPT-5.1-Codex by OpenAI, in 9 community votes, claude sonnet 4.5 wins 57% of head-to-head duels, context windows of 200K vs 400K, tested across 43 shared challenges. Updated April 2026.
Which is better, Claude Sonnet 4.5 or GPT-5.1-Codex?
Claude Sonnet 4.5 is the better choice overall, winning 57% of 9 blind community votes on Rival. Claude Sonnet 4.5 costs $3/M input tokens vs $1.25/M for GPT-5.1-Codex. Context windows: 200K vs 400K tokens. Compare their real outputs side by side below.
Key Differences Between Claude Sonnet 4.5 and GPT-5.1-Codex
Claude Sonnet 4.5 is made by anthropic while GPT-5.1-Codex is from openai. Claude Sonnet 4.5 has a 200K token context window compared to GPT-5.1-Codex's 400K. On pricing, Claude Sonnet 4.5 costs $3/M input tokens vs $1.25/M for GPT-5.1-Codex. In community voting, In 9 community votes, Claude Sonnet 4.5 wins 57% of head-to-head duels.
In 9 community votes, Claude Sonnet 4.5 wins 57% of head-to-head duels. Claude Sonnet 4.5 leads in Reasoning, while GPT-5.1-Codex leads in Web Design. Based on blind community voting from the Rival open dataset of 9+ human preference judgments for this pair.
Claude Sonnet 4.5 has the edge overall. In 9 blind votes, Claude Sonnet 4.5 wins 57% of the time.
Pick Claude Sonnet 4.5 for Reasoning. Pick GPT-5.1-Codex for Web Design.
Style Comparison
Claude Sonnet 4.5 uses 45.2x more emoji
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178 models fingerprinted across 32 writing dimensions. Free research.
185x
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We read every word. 250 models. 2.14 million words. This is what we found.
