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SwapClaude Sonnet 5.5
Anthropic's new Claude Sonnet 5.5 writes and answers questions in text, available to developers through an online service rather than as a free download.
Release page →The basics
Released
What it does
Knowledge cutoff
The latest events it learned about
Download
Where to use it
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Input
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How they score
Combined test score
Epoch Capabilities Index · Epoch AI
Claude Sonnet 5.5 scores 3 points higher.
Chat answers, by people's votes
LMArena text, adjusted for style · LMArena
Neck and neck: in blind votes, people pick each about as often as the other.
Building apps, by people's votes
LMArena WebDev · LMArena
In blind votes, people pick Claude Sonnet 5.5 over GPT-5.6 Sol about 71% of the time.
Green marks the better of the two on each row, red the other. Rows where one side isn't listed, or where the gap is too close to call, stay plain.
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Rankings from LMArena and Epoch AI, both CC BY 4.0, updated . Developer prices, context windows and knowledge cutoffs from the labs' own listings on models.dev and from OpenRouter. The app links go to each maker's own app when no source says exactly where the model is available.