Print and Paper sizes

Many paper size standards conventions have existed at different times and in different countries. Today, the A and B series of ISO 216, which includes the commonly used A4 size, are the international standard used by almost every country. However, in many countries in the Americas as well as in the Philippines, the North American series of paper sizes such as 'Letter' and 'Legal' is more prevalent.

Paper sizes affect writing paper, stationery, cards, and some printed documents. The international standard for envelopes is the C series of ISO 269.