Allowing the selection of paper size
There are several standards for paper size, but the most common ones are based on either the imperial or metric convention.
The imperial convention is common in North America. Bond paper is based on a 17-by-22-inch sheet, which divides into four 8.5-by-11 inch sheets. Another common size is the legal sheet, which is 8.5 by 14 inches. Some countries continue to use the traditional British foolscap sheets, which are 13.5 by 17 inches.
The metric convention, which is common in Europe and elsewhere, is exemplified by the German standard DIN 66008. Sheet sizes are based on the subdivision of the A0 paper, which has a dimension of 841 by 1189 millimeters. The closest equivalent to the 8.5-by-11 inch paper is the 210-by-297 millimeter A4 paper, which is longer but slightly narrower.
Paper size affects both hardware and software products. European A4 sheets do not fit into a North American printer tray, and reports that span the entire width of the 8.5-by-11 inch paper would overflow the A4 sheet. This guideline complements Guideline E11 – Accommodating different paper sizes.