Calculate paper sizes. A calculator for the German paper formats DIN A, B, C and D. These formats are internationally very common. Two sizes can be compared to each other, the output is in three different units. (here you can convert units of measurement). The ratios are rounded to three decimal digits. The ratio between width and height of a format is 1 to √2, rounded to whole millimeters. Two values of neighboring formats, like the widths of A5 and A4, have the same ratio. If you cut a sheet of paper with a DIN size in half along the longer side, you get a sheet of paper with the next smaller DIN size, i.e. with a number increased by 1, for example from A4 to A5.
Example: if you press "Calculate" without setting anything beforehand, the dimensions of DIN A 4 and DIN A 5 and the ratio of these two are calculated. The ratios are not exactly the square root of two for the lengths and two for the area, since they are rounded to full millimeters and the square root of two is an irrational number. For DIN A 4 to DIN A 6, the ratio of the lengths is approximately 2 and the area is approximately 4; for each further step apart, a length is multiplied by the square root of two and an area by two.
DIN stands for the Deutsche Institut für Normung (German Institute for Standardization). DIN A and DIN B are internationally valid formats that have been used in Germany since 1923 and have been adapted by many other countries. DIN A is by far the most commonly used. DIN C is still a valid national standard in Germany, but DIN D is hardly used anymore. DIN A 4 is the typical size for a sheet of paper. DIN B is a common format for many books, whereas DIN C is used for envelope sizes. All of these formats have the same length to width ratio, but start with different sizes for the 0 specification. For example, DIN A 0 has the size of one square meter, DIN B 0 is the square root of two square meters, DIN C 0 is the fourth root of two, i.e. 1.189, and DIN D 0 was the reciprocal of DIN C 0, i.e. 0.841.
Last updated on 06/30/2025. Author: Jürgen Kummer© Jumk.de Webprojects | Online Calculators | Imprint & Privacy | German: Rechner für Papierformate