What is A4 Paper?
The metric system of measurement for paper is used primarily throughout the world, with notable exceptions being the United States, Canada and Mexico. Paper-size measured metrically uses the unit “millimeter,” with 25.4mm equaling one inch. The International Standards Organization (ISO) sets forth in its document ISO 216 a series of (metric) paper sizes, each element having a length-to-width ratio of 1.414. A most commonly used size is A4, which measures 210mm x 297mm.
