B Paper Sizes

The B series paper sizes share the same aspect ratio of √2 as the more common A series. However, they follow a different sizing progression. While each A series sheet is half the area of the previous size, the B series sizes are based on the geometric mean. This means B1 falls between A0 and A1 in area at 0.707 m2. As a result, B0 is defined as 1 meter wide, with each successive B size having half that length of the previous sheet.

Though not as ubiquitous as the A series, the B series still serves many useful purposes. The modular scaling allows efficient printing of multiple A4 or letter pages on larger B sheets. Common applications take advantage of the intermediate sizes, including envelopes, music sheets, books, posters and printing presses. The B series can accommodate cases where A4 is too small but A3 is too large. Standard B sizes are also used for some specialized products like ID-3 passports and photography prints. Overall, the B series forms a companion system to the A series with its own advantages.