Paper sizes demystified

Paper comes in various sizes denoted as A, B, and C, with size A ranging from 4A0 to A10, size B from B0 to B10, and size C encompassing various sizes ranging from C0 to C10. The paper’s dimensions for length and width are expressed in millimetres (mm) and rounded off to the nearest millimetre.

A single leaf of printing paper or foolscap can serve as a starting point to simplify the comprehension of the diverse paper sizes. For instance, a size 4A paper is equivalent to one leaf of printing paper or foolscap and folding this paper lengthwise into two identical halves results in size A5, which happens to be the exact dimensions of a shorthand notebook. Continuing this folding pattern can create progressively larger sizes up to a size A10. Alternatively, placing a second leaf of printing paper or foolscap alongside the first one lengthwise produces the dimensions of a size A3. Repeat this process to generate even bigger paper sizes up to size 4A0, which measures approximately four square meters.

The letter B signifies books in book dimensions, with the size B6 approximating the dimensions of a typical paperback front cover. Should one double the dimensions of size A, the resulting size is B5 or larger, while dividing the measurements in half yields a size B7 or smaller.

Meanwhile, the letter C represents the container or casing, specifically envelopes, in this context. A size C envelope closely matches the dimensions of its size A equivalent, with ample room to accommodate the corresponding size A document. For example, a foolscap letter, which measures size 4A, can be securely enclosed in a size 4C envelope. However, folding the letter lengthwise means it can fit comfortably in a size 5C envelope, thus reducing the cost of the required envelope.

To delve further into paper size and related topics, kindly visit http://www.papersizes.org/.