A5

A5 is a paper size that is often used for notepads or pocket books.

Dimensions

A5 measures 148 × 210 millimeters or 5.83 × 8.27 inches. In PostScript, its dimensions are rounded off to 420 × 595 points.

Part of the ISO 216 standard

A5 is part of a set or range of page sizes, called the ISO A or ISO 216 standard. This international standard is based on the German DIN 476 standard from 1922. A5 is actually often referred to as DIN A5. The Japanese have adopted the same range of paper sizes in their JIS P 0138-61 standard.
By folding an A5 in two along its shortest side, you create an A6 document. Two A5 pages next to each other in a spread equals the A4 paper size. This way a range of paper sizes are created from A0 (which has a surface of one square meter) to A10. The height/width ratio remains constant (1:1.41 or the square root of 2) for all sizes. The dimensions always get rounded to the nearest millimeter.

Alternatives

None added yet.

Other sources of information

An elaborate yet easy to read page on the ISO 216 standard can be found here.