how big is a4

A4 paper size measures 210 millimeters by 297 millimeters, which is equivalent to 21 centimeters by 29.7 centimeters or approximately 8.3 inches by 11.7 inches. It is the most commonly used paper size worldwide and follows the ISO 216 international standard. The aspect ratio of A4 paper is the square root of 2, meaning its length divided by its width is about 1.414. This size is widely used for printing documents, letters, and standard sheets in offices and homes.