A7
A7 is a paper size that is typically used for large size Post-it notes. It can also be a practical size for tickets, since you can print 8 of them on an A4 sheet.
Dimensions
A7 measures 74 × 105 millimeters or 2.91 × 4.13 inches. In PostScript, its dimensions are rounded off to 209 × 298 points.
Part of the ISO 216 standard
A7 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. A7 is actually often referred to as DIN A7. The Japanese have adopted the same range of paper sizes in their JIS P 0138-61 standard.
By folding an A7 in two along its shortest side, you create an A8 document. Two A7 pages next to each other in a spread equals the A6 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.