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Paper sizes


John MacLulich

Many paper size standards and conventions have existed at different times and in different countries. Today, thankfully, there is one widespread international ISO (International Organization for Standardization) standard, ISO 216, which is also used in Australia. We are all familiar with sizes such as A4 and A3 – the paper sheets we can buy from the local newsagent for use in our home printers. But these are just two of many dozen different standard sizes available.

Standard paper sizes relate to writing paper, stationery, cards, and some printed documents. The standards also have related sizes for envelopes.

The advantages of using standard sizes when designing and printing documents include:

  • the ready availability of most off-the-shelf paper stocks
  • economical usage of resources – wastage is kept to a minimum when cutting standard size products from standard size sheets
  • page scaling and folding can be done in precise proportions – an A4 sheet folds in half to an A5 sheet, and so on

There is also a localised standard used in North America (including sizes such as Letter, Legal, Ledger, etc.) which, unfortunately, are the defaults in many page-layout programmes, most notably Microsoft Office products. It is straightforward to over-ride the default page sizes in software such as Microsoft Word or Excel or Publisher, but users of these products in Australia should beware that default documents produced using these programmes may not be suitably sized for commercial printing.

A, B and C-series sheet sizes

ISO paper sizes are all based on the ratio of √2 (the square root of 2), or approximately 1.4142.

The base A0 sheet of paper is defined to have an area of 1m². To the nearest millimetre, an A0 sheet size is 841 by 1,189 mm.

Successive paper sizes in the A-series (A1, A2, A3, and so forth) are defined by halving the preceding paper size along the larger dimension – folding the sheet in half.

In addition to the A-series, there is the less common B-series. B-series sheets are half-way in size between successive A-series sheets. So, B1 is between A0 and A1 in size – 707 x 1000mm. Many posters use B-series paper or a close approximation, such as 50 × 70 cm. B5 is a relatively common choice for books. The B-series is also used for envelopes and passports.

The C-series is used only for envelopes. C-series sheets are half-way in size between the A and B series sheets of the same number. So a C4 sheet is between an A4 sheet and a B4 sheet – 229 x 324mm. This means that C4 is slightly larger than A4, and B4 slightly larger than C4. The practical usage of this is that a letter written on A4 paper fits inside a C4 envelope, and a C4 envelope fits inside a B4 envelope.


Format A-series B-series C-series
ISO 216 Standard Metric Page Sizes
0 841 x 1189mm 1000 x 1414mm 917 x 1297mm
1 594 x 841mm 707 x 1000mm 648 x 917mm
2 420 x 594mm 500 x 707mm 458 x 648mm
3 297 x 420mm 353 x 500mm 324 x 458mm
4 210 x 297mm 250 x 353mm 229 x 324mm
5 148 x 210mm 176 x 250mm 162 x 229mm
6 105 x 148mm 125 x 176mm 114 x 162mm
7 74 x 105mm 88 x 125mm 81 x 114mm
8 52 x 74mm 62 x 88mm 57 x 81mm
9 37 x 52mm 44 x 62mm 40 x 57mm
10 26 x 37mm 31 x 44mm 28 x 40mm


Alternative sheet sizes

Before paper sheet sizes were standardised by ISO, literally dozens of alternative systems were in use. Even today, however, alternative systems are still common-place, in different countries, different industry groups and even different products and manufacturers. For example:

  • the ANSI standard is used in North America
  • the Arch standard is used for architectural purposes
  • index and business cards have a separate standard
  • photographs use yet another standard series of sizes
  • aeronautical charts are different again
  • Filofax and Franklin Planner have established their own proprietary standards
  • Newspapers( and other products printed web-offset) have an entirely different set of size standards

Envelope sizes

Envelope sizes are generally determined by their corresponding standard document sizes – so that common stationery sheet sizes such as A3, A4 and A5, can fit or can be folded to fit into a common envelope size.

So for example, an A4 sheet will fit into a C4 envelope, or can be folded in half to A5 size, to fit into a C5 envelope; or can be folded in half twice to fit into a C6 envelope; or can be folded in thirds (to 210 x 99mm) to fit into a DL envelope (220 x 100mm).

More information about envelope sizes can be found in Colours white paper on Envelopes.

Traditional, non-metric sheets sizes

The introduction of the metric system and the standardisation of paper sizes internationally has had enormous advantages. However, in the process, some of the jargon associated with printing and book-binding has been lost to a bygone era…

Imperial paper sizes, used in the United Kingdom and its territories, were based on curious names such as Royal, Emperor, Crown, Imperial, Elephant, Atlas, Princess, Duke and Duchess. And subsets of these sizes were named according to how many times the base sheet was folded, in order to produce a book or pamphlet. Thus common divisions included quarto, octavo, duo-decimo and others.

Today, traditional book printers and binders still use such sheet sizes by preference.


Further, detailed information about ISO 216 Paper Sizes is available on Wikipedia.

Images use on this web-page are from Wikipedia, by User:Bromskloss, via Wikimedia Commons. They are licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.