A Format

With small dimensions of approximately 4.3" x 7" (110mm x 178mm), the A Format has a compact surface area around 30 square inches or 194 square cm. Part of the ISO 216 international standard paper sizes, A Formats get their name from being one half of the area of the next larger A size. The A Series scales down mathematically from the largest A0 to save paper efficiently. Especially popular outside of North America for mass market paperbacks, A Format strikes a handy balance of portability and legible text formatting. Originating from efforts to standardize paper sizes by the German DIN in the 1920s, A Formats align with the metric system. The 4.3" x 7" size can comfortably fit around 175-250 pages printed on both sides. With adoption globally but less so in the US, A Formats are useful for paperback novels, small textbooks, brochures, and catalogs when minimal size and waste are desirable. Its success stems from striking a versatile compromise between compactness and smooth readability.