A1 size is a standard paper dimension that measures 594 millimeters by 841 millimeters, or approximately 23.4 inches by 33.1 inches. It is part of the A series of paper sizes defined by the ISO 216 standard, which is widely used in many countries around the world. A1 is commonly used for posters, architectural drawings, and large diagrams due to its ample space for detailed information. The A1 size is half the area of A0 size and double the area of A2 size. This makes it a versatile choice for various applications, including presentations and artwork. The A series sizes are designed to be easily scaled up or down, maintaining the same aspect ratio, which simplifies printing and design processes.