International Paper Sizes.

Many printing companies, and individuals want to be able to check standard paper sizes easily.

We have added a convenient chart for you to check paper sizes.

The International paper size standard, ISO 216, is based on the metric system, with the base format being a sheet of paper measuring 1m² in area.

By 1977 A4 was the standard letter format in 88 of 148 countries, and today only the U.S. and Canada have not adopted the system.

The largest standard size, A0, has an area of 1m². The long side of the sheet is calculated by taking the 4th root of 2, approximately 1.189, and the short side is the inverse of that number, approximately 0.841, and multiplying by one metre. A1 is formed by cutting a piece of A0 in half, which retains the aspect ratio. This particular measurement system was chosen in order to allow folding of one standard size into another, which cannot be accomplished with traditional paper sizes.

Brochures are made by using material at the next size up i.e. material at A3 is folded to make A4 brochures. Similarly, material at A4 is folded to make A5 brochures.

It also allows scaling without loss of image from one size to another. Thus an A4 page can be enlarged to A3 and retain the exact proportions of the original document.

The scalability also means that less paper (and hence money) is wasted by printing companies.

Grammage(Weight)

Throughout the world, except in regions using US paper sizes, the product of thickness and density of paper is expressed in grams per square metre (g/m²). This quantity is commonly called grammage in both English and French (ISO 536), though printers in most English-speaking countries still refer to the "weight" of paper, i.e. 80 gsm.

Typical office paper has a grammage of 80 g/m², therefore a typical A4 sheet (1/16 m²) weighs 5g.

The unofficial unit symbol "gsm" instead of the official "g/m²" is also occasionally encountered in English speaking countries.

While paper is measured by weight, card is measured by thickness in micrometres.