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Paper is supplied in many sizes, most of us are aware of the 'A' size series, however as our paper is sourced from around the world only a small amount is available on this format.

This is a basic guide of these sizes and hopefully should be of use.

A, B & C Sizes

When browsing our catalogue you will notice that papers are supplied in a variety of sizes.

The most modern paper sizes are the 'A', 'B' and 'C' sizes, whose dimensions are listed below.

These sizes have been adopted throughout most of the world with the notable exception of the USA and Canada.

The largest standard size, A0, has an area of 1meter squared. 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 sized brochures.

There is also a much less common B series. The area of B series sheets is the geometric mean of successive A series sheets. So, B1 is between A0 and A1 in size. While less common in office use, it is used for a variety of special situations. Many posters use B-series paper or a close approximation, such as 50 cm×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. The area of C series sheets is the geometric mean of the areas of the A and B series sheets of the same number; for instance, the area of a C4 sheet is the geometric mean of the areas of an A4 sheet and a B4 sheet. 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 sturdier B4 envelope.

North American Paper Sizes

In 1995,the American National Standards Institute adopted ANSI which defined a regular series of paper sizes based upon the de facto standard 8.5" x 11" "letter" size which it assigned "ANSI A". This series also includes "ledger"/"tabloid" as "ANSI B". This series is somewhat similar to the ISO standard in that cutting a sheet in half would produce two sheets of the next smaller size. Unlike the ISO standard, however, the arbitrary aspect ratio forces this series to have two alternating aspect ratios. The ANSI series is shown below.

SRA Format

A series of standard sizes for untrimmed paper. They are slightly larger than the corresponding A-series sizes. Printers buy untrimmed paper, bind it and then trim it down to standard A- sizes.

Traditional Inch Based Sizes

Traditionally, a number of different sizes were defined for large sheets of paper, and paper sizes were defined by the sheet name and the number of times it had been folded. Thus a full sheet of "Royal" paper was 25 × 20 inches and "Royal Octavo" was this size folded 3 times, so as to make eight sheets, and was thus 10 by 6¼ inches.

Imperial sizes were used in the United Kingdom and its territories.

* The sizes marked with an asterisk are still in use in the USA and some papers are still manufactured based on these sized, especially Imperial which is a common hand-made or mould-made paper size.

Traditional Bookmaking Sizes

Foolscap folio is often referred to simply as 'Folio' or 'Foolscap'. Similarly, 'Quarto' is more correctly 'Copy Draught Quarto'.

Many of these sizes were only used for making books and would never have been offered for ordinary stationery purposes.

Japanese Paper Sizes

The JIS A-series is identical to the ISO A-series. The area of B-series paper is 1.5 times that of the corresponding A-paper, so the length ratio is approximately 1.22 times the length of the corresponding A-series paper. The aspect ratio of the paper is the same as for A-series paper. Both A- and B-series paper is widely available in Japan and most photocopiers are loaded with at least A4 and B4 paper.

Many papers, or sheets of Washi are made by individuals or families and as such their papers do not conform to traditional or modern paper sizes.

There are also a number of traditional paper sizes, which are now used mostly only by printers. The most common of these old series are the Shiroku-ban and the Kiku paper sizes. Another popular printmaking size is Obosho at 394 x 530mm. For ukiyo-e prints this is cut in half to 265 x 394mm and called oban. This can then be halved again and is called chuban.