## B1 size is widely used as a poster or an enlargement in many countries of the world except North America, which chose other standards.

The dimensions of B1 size is 100 x 70.7 cm or 39.37 x 29.83 inches. It has an area of 0.707 m², which corresponds to 0.84 square yards, 7.53 square foot or 1085 square inches. Its printable surface is slightly lower when you apply the usual printing margins.

If you want to calculate the weight of one or more B1 sheets, it is important to refer to the weight of the paper used, as it is expressed in g/m². However, we know that the B1 size has an area of 0.707 m². We can therefore calculate that, for a 120 g/m² paper, a sheet of B1 weighs 120 x 0.707 = 84.84 grams.

B1 format is derived from the ISO 216 standard, adopted internationally in 1975. It comes from the German standard DIN 476, adopted in 1922 on a proposal from Walter Portsmann. He had appreciated the arguments of Lichtenberg, a professor who had invented the √2 ratio, which implies a ratio of 1.4142 between length and width (a/b = 2b/ a = √2). This proportion keeps the contents of a page when enlarged or reduced.

The B1 size is ½ a B0 (for the format above), but also 2 B2 sheets, 4 B3 sheets... B1 width is the same as the B2 length, and its length is the same size as B0 width.