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Claude Opus 5.5
Anthropic's new Claude Opus 5.5 writes text and answers questions, offered to developers and paying users, not free to download.
Release page →The basics
Released
What it does
Knowledge cutoff
The latest events it learned about
Download
Where to use it
Price and limits, for developers
Input
Per million tokens
Output
Per million tokens
Cached input
Per million tokens
Context window
How much it takes in at once
Longest answer
How they score
Combined test score
Epoch Capabilities Index · Epoch AI
Claude Opus 5.5 scores 33 points higher, a big step.
Chat answers, by people's votes
LMArena text, adjusted for style · LMArena
Only Claude Opus 5.5 is in this ranking, which lists the most-voted models.
Building apps, by people's votes
LMArena WebDev · LMArena
Only Claude Opus 5.5 is in this ranking, which lists the most-voted models.
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.