## B9 size is the second smallest size in B range, which was standardized by ISO 216. The only smaller standardized B format B10.

The proportions are always maintained between B formats, regardless of their number (0 to 10). Indeed, the Lichtenberg’s ratio, which was taken over by Portsmann and DIN, and that inspired ISO 216 (international standard) is always respected: 1.4142 (a / b = 2b / a = √ 2). A B9 sheet is always twice as large as a B10 sheet, and twice smaller than B8. Therefore, a B9 size is obtained by folding a B8 format in the direction of its width.

The content of the page is then always adapted to the sheet when enlarging or reducing.

The surface of B9 sizeis 0.0027 m² (or 0.02 square foot, 3.1 square inches). It is most often used for flyers or labels, often by professional printers, because B formats do not have a large enough notoriety for B personal printers to be produced.

Format B9 measures 62 x 44 mm or 2.44 x 1.73 inches. Its length corresponds to the width of B8, and its width corresponds to the length of B10. When printed, it respects margins that make its printable surface more limited.

The B9 format corresponds to ¼ a B7, ½ a B8 for larger sizes, and two B10 sheets for the only smaller B size.

If one wishes to calculate the weight of a B9 sheet, its area (0.0027 m²) must be compared to weight of paper. For example, if you choose a paper of 80 g/m², the weight of a sheet will be 0.0027 x 80 = 0.216 grams.