C Format

With dimensions of approximately 5.3" x 8.5" (135mm x 216mm), the C Format has a surface area around 45 square inches or 290 square cm. Part of the ISO 216 standard paper sizes, C Formats scale down mathematically from larger A sizes to efficiently save paper. Especially popular outside North America for trade paperbacks, C Format is between B and A Formats in size. Originating from German efforts to standardize in the 1920s, C Formats align with the metric system. The 5.3" x 8.5" size can comfortably fit around 250-300 pages printed on both sides. With wide adoption globally but less commonly in the US, C Formats hit a versatile sweet spot for paperback fiction, textbooks, and manuals seeking compactness. Its success stems from striking a useful balance of portability and smooth readability. Though not a household name, the ISO C Standard streamlines consistent sizing between books, boxes, binders and more internationally. Its handy metrics bridge mass market paperbacks and larger trade sizes.