Paper sizes in series A

The A series of paper is the most commonly used worldwide, with only the US and Canada (some parts of Mexico) not currently conforming to the ISO 216 (international standard).

Paper sizes are standardized formats that are used for writing, printing and design. They are defined by the International Organization for Standardization (ISO) and are based on the metric system. The most commonly used paper sizes are:

  • A4: 210 x 297 mm (8.27 x 11.69 inches)
  • A3: 297 x 420 mm (11.69 x 16.54 inches)
  • A5: 148 x 210 mm (5.83 x 8.27 inches)
  • A6: 105 x 148 mm (4.13 x 5.83 inches)

These are the most commonly used paper sizes, there are other formats as well like:

  • C series, D series, E series, F series, G series, etc.
A4 in pixels

All paper sizes in millimeters and inches


Read more about the different A papers:

About the ISO standard

The International Organization for Standardization (ISO) first published its international standard for paper sizes in 1975, although the format itself is based on the German DIN 476 standard that was first introduced in 1922. The ISO standard for paper sizes is known as ISO 216 and it defines a series of paper sizes based on a single aspect ratio of the square root of two (1:√2). This aspect ratio means that the ratio of the length to the width of each paper size is the same, and each size is simply half the area of the next larger size.

Other paper sizes

Click if you are looking for measurements and information about B size papers or paper sizes in the US standards (used in Canada and Mexico also).