ISO 216 metric sizes are the standard for Europe and most of the world outside the US. The ISO 216 system is based on the surface area of a sheet of paper, not on a sheet’s width and length. It was first adopted in Germany in 1922 and generally spread as nations adopted the metric system.
- A sizes describe paper.
- B sizes are larger and used for printing as they include a trim and
- C sizes are for envelopes to contain the A sizes.
In the ISO paper size system all sheet sizes have a width to height ratio of the square root of two (1:1.4142). By placing two sheets of A series paper next to each other, or by cutting one in half parallel to its shorter side, the resulting sheet will again have the same width to height ratio. The largest standard size paper is A0 (A zero), measuring one square meter (approx. 1189 × 841 mm). Two sheets of A1, placed upright side by side fit exactly into one sheet of A0 laid on its side. Similarly, two sheets of A2 fit into one sheet of A1 and so forth. Common sizes used in the office and the home are A4 and A3 (A3 is the size of two A4 sheets). In papers for printing, the prefix R or SR is added to the A size to denote a slightly larger sheet to allow for machine grip and registration in the print process eg for full bleed images.
|Size||Height x Width (mm)||Height x Width (in)|
|4A0||2378 x 1682 mm||93.6 x 66.2 in|
|2A0||1682 x 1189 mm||66.2 x 46.8 in|
|A0||1189 x 841 mm||46.8 x 33.1 in|
|A1||841 x 594 mm||33.1 x 23.4 in|
|A2||594 x 420 mm||23.4 x 16.5 in|
|A3||420 x 297 mm||16.5 x 11.7 in|
|A4||297 x 210 mm||11.7 x 8.3 in|
|A5||210 x 148 mm||8.3 x 5.8 in|
|A6||148 x 105 mm||5.8 x 4.1 in|
|A7||105 x 74 mm||4.1 x. 2.9 in|
|A8||74 x 52 mm||2.9 x 2.0 in|
|A9||52 x 37 mm||2.0 x 1.5 in|
|A10||37 x 26 mm||1.5 x 1.0 in|
In UK imperial measurements are still used alongside the metric system, including terms like Foolscap, Crown and Demy.
Most commercial paper sold in North America is cut to standard paper sizes based on customary units and is defined by the length and width of a sheet of paper.