A5 size is a paper dimension that measures 148 millimeters by 210 millimeters, or approximately 5.8 inches by 8.3 inches. It is part of the A series of paper sizes defined by the ISO 216 standard, which is widely used around the world. A5 is half the size of A4, making it a popular choice for notebooks, flyers, and brochures. This size is often used for personal planners, invitations, and small booklets due to its convenient dimensions. A5 paper is easy to handle and fits well in bags, making it a practical option for everyday use.