how big is a1 size

The A1 size measures 594 × 841 millimeters, which is equivalent to 59.4 × 84.1 centimeters or 23.4 × 33.1 inches. It is exactly half the size of an A0 sheet and twice the size of an A2 sheet. The A1 format follows the ISO 216 international paper size standard and has an aspect ratio of 1:√2, making it ideal for posters, architectural drawings, and advertising materials due to its large size and clear visibility.