The A4 Landscape size (3508×2480px)
A4 in landscape orientation is the same 210 by 297mm sheet turned on its side, which at 300 DPI measures 3508 by 2480 pixels. The wide 1.41:1 format is a favorite for certificates, presentation handouts, panoramic photo prints, brochures, and infographics, where a horizontal canvas gives a natural left-to-right reading flow that portrait cannot match.
Choosing the exact 3508x2480 pixel size means your artwork maps precisely onto a physical A4 page with no scaling or unexpected margins, and at 300 dots per inch every line of text, chart label, and photographic detail stays sharp under close inspection. The landscape shape also pairs neatly with 16:9-ish content like slide exports and wide charts, though remember A4 is slightly less elongated than a 16:9 screen, so a full-screen slide will get letterboxed or cropped a touch when placed on the page.
As with any print job, handle bleed and safe margins. Extend any full-bleed background or photo a few millimeters past the 297x210mm trim so cutting never reveals a white sliver, and keep titles and signatures inside a comfortable margin from the edge. Certificates in particular benefit from a decorative border set safely inside the trim. Everything here resizes 100% in your browser with no upload and for free, so your document stays private on your device. Because printer requirements differ, confirm bleed, DPI, and color settings before committing to a professional print run.