Samsung Galaxy S25 Ultra: Screen Size & CSS Viewport

The Samsung Galaxy S25 Ultra represents the pinnacle of the S25 family, combining the largest screen in the lineup with an integrated S Pen at a CSS viewport of 412×917. The S Pen makes precision selection, form filling, and handwriting on web content practical in ways that pure touch input is not.

Developers of web applications with text input fields, drawing canvases, or annotation features should specifically test S Pen interactions at 412px. Hover states triggered by the S Pen hovering above the screen (without touching) are detectable via pointer events, enabling tooltip-style previews and context hints before an ink stroke lands — a progressive enhancement worth implementing if your audience includes S Pen users.

Gorilla Armor 2 is the first S Ultra with a factory-applied anti-glare coating, meaning the S25 Ultra is now optimized for bright outdoor viewing. Combined with 2600 nits peak brightness, contrast-sensitive design elements — subtle dividers, muted background colors, ghost-white text — that pass contrast checks in normal lighting may become invisible in sunlight. Run your color contrast audits against your actual color palette at extreme brightness values to catch these edge cases.