The international paper size standard, ISO 216, is based on the German DIN 476 standard for paper sizes. ISO paper sizes are all based on a single aspect ratio of square root of 2, or approximately 1:1.4142. The base A0 size of paper is defined to have an area of one m². With the given aspect ratio of square root of two, this corresponds to a piece of paper which its longer side is one metre multiplied by the square root of the square root (that is, the fourth root) of two and the shorter side being the reciprocal of this value. Rounded to millimetres the A0 paper size is 841 by 1,189 millimetres (33.1 × 46.8 in).Not a lot of people know that. The UK adopted this standard in 1959, though I do not recall anyone making much of a fuss at the time. Before then (and indeed for a number of years thereafter) we commonly used foolscap, which was slightly larger than A4.
Successive paper sizes in the series A1, A2, A3, and so forth, are defined by halving the preceding paper size along the larger dimension. The most frequently used paper size is A4 (210 × 297 mm).
I suppose that it’s too late to demand that we rescind our adherence to the international standard. And why would one want to? Maybe I would just like to be contrary. Is globalisation such a good thing? Anyway, unlike the youth of today, I still think in Fahrenheit.
Have a nice evening.