OnePlus 13: Screen Size & CSS Viewport

The OnePlus 13 ships with the brightest display ever put in a consumer smartphone at 4500 nits peak brightness — a level that fundamentally changes how web content renders in outdoor environments. At this brightness, color perception shifts: vibrant oranges appear almost fluorescent, dark grays wash out, and thin borders become near-invisible. If your design uses light-on-dark or low-contrast color pairings, they will be even harder to read on the OnePlus 13 in direct sunlight than on any other device tested to date.

Its CSS viewport of 412×917 is shared with the Galaxy S25 Ultra, confirming this as a standard premium Android viewport. The 19.8:9 aspect ratio is slightly taller than typical 19.5:9 phones, pushing fold position and scroll depth slightly lower.

The Ceramic Guard front glass combines scratch resistance with a premium tactile feel that encourages extended screen interaction. OnePlus users tend to be tech-savvy early adopters who will notice layout inconsistencies quickly. If your site has unresolved 412px issues — such as grid overflow, tight padding, or truncated text — this audience will encounter and report them. Use 412px as a primary mobile test width alongside the more common 390px.