B4

The B4 paper size is part of the ISO B series used for large-format printing and technical drawings. With dimensions of 250 x 353 mm, B4 is the fifth largest size in the B system. It retains the distinct height-to-width ratio of 1:√2 (approximately 1:1.4142) that enables efficient scaling between incremental sizes.

With a surface area of 0.09 square meters, B4 provides a substantial print space while maintaining portability. Its versatile dimensions make B4 suitable for wide charts, posters, infographics, and visual plans requiring a manageable large format. The origins of B4 date back to the German DIN 476 standard from 1922 before being adopted as an ISO standard in 1975. Today, B4 is popular across fields like architecture, engineering, manufacturing, and graphic design for presenting detailed visual information on posters, in manuals, and more. As the smallest standard B size, B4 offers utility across large-format documents.