Paper Sizes: A Handy Guide Getting your head around paper sizes can be difficult, but with our simple guide, you’ll be sure to know your A4 paper measurements from your 4A0!

A Paper Size Guide

The ISO 216 refers to the international standardised paper sizes which have been in operation across the world from the mid twentieth century, derived from the original German standard. The notable exceptions are Canada and the USA,which have their own paper size guide in the form of the North American sizes.

A size chart illustrating the ISO A series and a comparison with American letter and legal formats. Image Copyrights © Creative-commons – Paper Sizes

A0 isthe largest of the officially recognised ‘A’ paper sizes, with A8 being the smallest. The paper sizes are doubled as the number gets smaller i.e. A4 paperis double the size of A5. Most people would recognise the A4 paper size as thestandard size for a business letter, or for a domestic printer, and when usingthe ‘A’ paper size guide, people often use the A4 size as a starting point forwhich to relate other sizes.

The‘A’ paper sizes are defined by their distinctive proportions, which sees thelength divided by the width equate to 1.4142: this will be the case no matter which paper size is measured within the ‘A’ scale. However, small discrepanciesin sizes are allowed to exist in line with ISO 216, which vary depending on thesize of the paper. Plus or minus 1.5mm is allowed for dimensions on pages up to150mm, 2mm for dimensions from 150 to 600mm (the A4 paper size falls into this category), and 3mmfor dimensions exceeding the higher end of this range. Moreover, the area of A0will always be 1 square metre, plus or minus the tolerated dimensions asoutlined above.

Oversized A paper does exist, but it is not officially recognised in the same way that other sizes, such as the A4 paper measurement are. These are known as 4A0and 2A0 and draw on the original German DIN 476 standard, and areused for oversized pieces which do not fit into these paper sizes. A paper size calculator is also a great way to calculate the size paper which is most appropriate to your printing needs, as often it can be confusing which will best suit your printing needs, particularly if you already have a size in mind and need to see how that translates into predefined paper standards.Moreover, this is a handy tool when converting between North American and the International Standardised paper sizes.