Different countries have different standards for paper sizes, but one of the most commonly used international standards is the ISO 216. The ISO 216 paper size system is an international standard that is used in copy and print devices that defines paper sizes. Based on the metric system, the ISO paper size system uses a height-to-width ratio with an aspect ratio of 1 to 1.414 (the square root of 2). If a sheet is cut into two, the resulting halves are the same proportions as the original.

The most common series in the ISO 216 standard is the A series, with A4 (210x297mm) being the standard letterhead paper size. In this series all successive paper sizes are derived from the base standard A0, which is a sheet of paper measuring 1 square meter or 841 x 1189mm. The ISO standard specifies the following for A paper format sizes (mm);

• A0   841 W 1189

• A1   594 W 841

• A2   420 W 594

• A3   297 W 420

• A4   210 W 297

• A5   148 W 210

• A6   105 W 148

• A7   74 W 105

• A8   52 W 74

• A9   37 W 52

• A10  26 W 37

In addition to the A paper sizes, this ISO standard also defines paper sizes B (ISO 216) and C (ISO 269), which are also square root of two formats. The B series contains intermediate sizes for the A series but are sizes that are not frequently used. The C series The C series of sizes is for envelopes, where the C4 (229 x 324mm) is defined under ISO 269 and is most often used with A4 size paper. Likewise the C5 envelope is perfect for folded down A5 paper and so on. The ISO standards for sizes B and C paper formats are as follows;

North American Paper Size Standards
The United States and Canada do not widely use the ISO standard paper sizes, and in fact are the only industrialized countries not to use it. Instead, the United States uses the Letter, Legal and Executive system, and Canada uses a P-series of sizes. Unlike the international ISO 216 standard, these paper sizes are not based on a proportional aspect ratio system for size.

The most commonly used sizes in U.S. office applications and also one or various technical paper sizes, as defined by the American National Standard (mm):

• Letter: 216 x 279

• Legal: 216 x 356 

• Executive: 190 x 254 

• Ledger/Tabloid: 279 x 432 

• Technical drawing (A) 216 W 279

• Technical drawing (B) 279 W 432

• Technical drawing (C) 432 W 559

• Technical drawing (D) 559 W 864

• Technical drawing (E) 864 W 1118

The Canadian standard CAN 2-9.60M defines six formats (mm);

• P1: 560 x 860

• P2: 430 x 560 

• P3: 280 x 430 

• P4: 215 x 280

• P5: 140 x 215

• P6: 107 x 140 

The Canadian P-series of paper sizes are the U.S. paper sizes rounded to metric dimensions. For example, the U.S. letter size is 216 x 279 mm compared to the Canadian P4 size which is 215 x 280 mm. The equivalent ISO 216 standard for this size would be the A4 with a size of 210 x 297mm.

Paper Size Standards In Other Countries

• The ISO paper size standard is actually based on the German DIN paper specifications (DIN 476). The DIN specification, however, includes specifications for paper sizes larger than A0 that are not included in the ISO standard.

• In Sweden the SIS standard also follows the ISO (A, B and C) standard but again expands on it to add formats D through to G.

• In Japan the standard is JIS, A and B series. The JIS A series matches the ISO A series sizes, but the B sizes are larger than the ISO B series sizes.

The most noticeable difference in these paper sizes is that when using the ISO standard based on an aspect ratio, if using a copier machine you can magnify to enlarge A4 to A3 and also equally reduce A3 down to A4. Copiers and similar devices outside of North America will have built in magnification options. Copiers in North America do not have magnification functions, but instead will usually contain separate input trays for letter or legal sizes of paper. These differences can come as quite a surprise to those traveling in different countries who want to use such devices. Standard US and Canadian sizes of paper are also not readily available in many other countries where the ISO standard is used.

Vangie 'Aurora' Beal - Writer, www.Webopedia.com
Last updated: August 03, 2007
 

Japanese Papers for Printing
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International standard paper sizes
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Notes on The Standardization of Paper Sizes (PDF)
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Paper Sizes and Paper Weight: Metric and US Standards
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