## A7 size come into the category of formats that can’t be written. It is indeed too small to accommodate the written text, and then only be used in professional printing.

A7 format is commonly used for making flyers or large cards. It is also used to print menus.

This format was first standardized by the German DIN 476 in 1922, on the proposal of Walter Portsmann. This is based on a letter of Lichtenberg (1786), explaining the interest √2 ratio in length / width proportions. This standard was taken up in 1975 by the international standard ISO 216.

The √2 ratio has an very special advantage, because it keeps proportions in order that a sheet folded in the direction of its width is still √2 ratio. So for a A7 size, proportioned √2 (ie 1.4142 (a / b = 2b / a = √ 2)), we know that we can get a A8 bending, and A6 doubling. Both formats will retain proportions. A A7 is equal to ¼ an A5, ½ an A6, but also 2 A8 sheets, 4 A9 sheets...

Surface of A7 is 0.0078 m², with dimensions of 105 x 74 millimeters or 4.13 x 2.91 inches. We can also express the A7 surface in square yards: 0.01, square foot: 0.09, or square inches: 12.4.

The weight of an A7 sheet of paper refers to that of a sheet of A0 size (which measures 1 m²). For paper weighing 100 g/m², we will have a weight of 100 g for A0 sheet, that means, for A7 (which is 128 times smaller), 100/128 = 0.78 grams.