Crunchyroll does not natively stream in 4K for most content. Instead, they use a real-time AI upscaling algorithm called Anime4K within the browser/client-side.
Access to the library, including higher quality upscaled content, requires a subscription. Viewing and Quality Management
or devices for using the WebGLShader AI upscaler? How To Increase Quality on Crunchyroll
To ensure the best experience, users can adjust settings to "Highest" within the video player.
The AI upscaling performs better with higher internet speeds, and the system uses adaptive bitrate to adjust quality.
Based on the information regarding Crunchyroll's video scaling and 4K capabilities in 2026, here are the key takeaways from the search results: