A5 Size : Make the Right Choice On the surface, paper sizes can become a little bewildering and unfathomable when compared to one another in the A-series. However, once you know how each size correlates, ordering the right paper type for your business is a breeze! An internationally recognised ISO 216 standard paper size , A5 paper measures 148 x 210mm. By folding an A5 paper type in two along the shortest side, you can create an A6 document. Alternatively, placing two A5 pages next to each ... Learn about the A series paper sizes and dimensions defined by the ISO 216 standard. A5 is 148 x 210 mm or 5.8 x 8.3 inches, half the size of A4. The ISO 216 A-series international standard paper sizes are defined by halving area from A0 down. Folding parallel to shorter sides scales efficiently. Learn about how the A-series allows consistent sizing perfect for brochures, printing, and more.