Paper Sizes

ISO 216 specifies tolerances for the production of A series paper sizes as follows:

• ±1.5 mm (0.06 in) for dimensions up to 150 mm (5.9 in)
• ±2 mm (0.08 in) for lengths in the range 150 to 600 mm (5.9 to 23.6 in)
• ±3 mm (0.12 in) for any dimension above 600 mm (23.6 in)

A Series Paper Sizes Defined

The, A series paper sizes are defined in ISO 216 by the following requirements:

• The length divided by the width is 1.4142
• A0 size has an area of 1 square meter.
• Each subsequent size A(n) is defined as A(n-1) cut in half parallel to its shorter sides.
• The standard length and width of each size is rounded to the nearest millimeter.

Note: For reference the last item is there because the root 2 aspect-ratio doesn’t always give a whole number.

ISO Guidelines

ISO 216 specifies international standard (ISO) paper sizes used in most countries in the world today, although not in Canada, the United States, Mexico, Colombia, or the Dominican Republic. The standard defines the “A” and “B” series of paper sizes, including A4, the most commonly available paper size worldwide. Two supplementary standards, ISO 217 and ISO 269, define related paper sizes; the ISO 269 “C” series is commonly listed alongside the A and B sizes.

All ISO 216, ISO 217 and ISO 269 paper sizes (except some envelopes) have the same aspect ratio, √2:1, within rounding to millimetres. This ratio has the unique property that when cut or folded in half widthways, the halves also have the same aspect ratio. Each ISO paper size is one half of the area of the next larger size in the same series.

The A series paper sizes are now in common use throughout the world apart from in the US, Canada and parts of Mexico. The A4 size has become the standard business letter size in English speaking countries such as Australia, New Zealand and the UK, that formerly used British Imperial sizes. In Europe the A paper sizes were adopted as the formal standard in the mid 20th century and from there they spread across the globe.

ISO 216 specifies tolerances for the production of B series paper sizes in the same way as for A series paper sizes, the specific details of which are as follows:

• ±1.5 mm (0.06 in) for dimensions up to 150 mm (5.9 in)
• ±2 mm (0.08 in) for lengths in the range 150 to 600 mm (5.9 to 23.6 in)
• ±3 mm (0.12 in) for any dimension above 600 mm (23.6 in)

B Series Paper Sizes Defined

The B series paper sizes are defined in ISO 216 in the following way.

The B series paper sizes were created in order to provide paper sizes that weren’t covered by the A series, but also use an aspect ratio of 1:root2. B sizes are defined as size B(n) being the geometric mean of size A(n) and size A(n-1). The Geometric Means of 2 numbers being the square root of the product of the two numbers.

This system gives a useful property for enlarging and reducing documents in that the enlargement from A(n) to B(n) is the same as that from B(n) to A(n-1).

As with the A series paper sizes, the standard lengths and widths are rounded to the nearest millimeter.

ISO Guidelines

ISO 216 specifies international standard (ISO) paper sizes used in most countries in the world today, although not in Canada, the United States, Mexico, Colombia, or the Dominican Republic. The standard defines the “A” and “B” series of paper sizes, including A4, the most commonly available paper size worldwide. Two supplementary standards, ISO 217 and ISO 269, define related paper sizes; the ISO 269 “C” series is commonly listed alongside the A and B sizes.

All ISO 216, ISO 217 and ISO 269 paper sizes (except some envelopes) have the same aspect ratio, √2:1, within rounding to millimetres. This ratio has the unique property that when cut or folded in half widthways, the halves also have the same aspect ratio. Each ISO paper size is one half of the area of the next larger size in the same series.

The A series paper sizes are now in common use throughout the world apart from in the US, Canada and parts of Mexico. The A4 size has become the standard business letter size in English speaking countries such as Australia, New Zealand and the UK, that formerly used British Imperial sizes. In Europe the A paper sizes were adopted as the formal standard in the mid 20th century and from there they spread across the globe.

Tolerances specified in ISO 216 for the C series envelope sizes are the same as for A & B series paper sizes and are as follows:

• ±1.5 mm (0.06 in) for dimensions up to 150 mm (5.9 in)
• ±2 mm (0.08 in) for lengths in the range 150 to 600 mm (5.9 to 23.6 in)
• ±3 mm (0.12 in) for any dimension above 600 mm (23.6 in)

C Series Envelope Size Definitions

C envelopes sizes are defined as the geometric mean of the A and B sizes with the same number i.e. C4 dimensions are the geometric mean of A4 and B4. This produces a size between the two that makes an envelope that will neatly hold the A series paper of the same size, thus a C4 envelope is perfect for an A4 sheet of paper unfolded.

It should be noted that C format envelopes also have an aspect ratio of 1:root2 and because of this an A4 sheet folded parallel to its shortest sides will fit in a C5 envelope and folded twice will fit a C6 envelope.

The C4 envelope can contain an A4 sheet, the C5 envelope can contain an A4 sheet folded in half (an A5 sheet) and the C6 envelope can contain an A4 sheet folded in half twice (an A6 sheet). This is the reason that you will sometimes see these envelope sizes being referred to as A4 envelope size, A5 envelope size and A6 envelope size.

The RA and SRA paper formats are defined by ISO 217 “Paper – Untrimmed Sizes” and cover untrimmed raw paper for commercial printing. The RA and SRA sizes are slightly larger than the corresponding A series sizes to allow for bleed on printed material that will be later trimmed to size, often for bound publication.

RA stands for “raw format A” and is conceptually defined as being 105% of the A series size, thus as A0 has an area of 1 square meter RA0 has an area of 1.05 square meters. SRA stands for “supplementary raw format A” and is conceptually defined as being 115% of the A series size, so a sheet of SRA0 paper has an area of 1.15 square meters. In reality the sizes for RA0, RA1, RA2, SRA0, SRA1 and SRA2 are rounded to the nearest centimeter and sizes for RA3, RA4, SRA3 and SRA4 are rounded to the nearest half centimeter.

SRA1+, SRA2+, SRA3+ and SRA3++

Some sizes that are becoming more popular due to their extra width being good for newer printing machines are SRA1+, SRA2+ SRA3+ and SRA3++. These SRA plus sizes give a little extra width for a printer to grab the edge of the paper to turn it over for double-sided printing, as the printer will slightly mark the paper when it picks it up. It should be noted that these sizes are not defined by an ISO standard and have emerged from industry needs.

ANSI (American National Standards Institute) defined a regular series of paper sizes based around the Letter (8.5″ x 11″) format, with this becoming the A sizes and larger sizes being B,C,D & E. Surprisingly these ANSI standard sizes were defined in 1995 well after the ISO standard sizes. ANSI A sized paper is commonly referred to as Letter and ANSI B as Ledger or Tabloid.

Unlike the ISO standard sizes which have the single aspect ratio of 1:root2, ANSI standard sizes have two aspect ratios 1:1.2941 and 1:1.5455 which means that enlarging and reducing between the sizes is not as easy as with the ISO sizes and leaves wider margins on the enlarged/reduced document.

Other paper size standards issued by ANSI include:

• ANSI INCITS 151-1987 – Bond Papers and Index Bristols – Common Sheet Sizes
• ANSI INCITS 96-1983 – Forms, Paper Sizes for Single-Part Continuous Business

North America also has a special series of paper sizes defined for architectural purposes, in general these have aspect ratios of 4:3 or 3:2. These aspect ratios are very similar to the aspect ratio used for computer screens.

North America, including the US, Canada and parts of Mexico, is the only area of the first world that doesn’t use the ISO 216 standard paper sizes, instead they use Letter, Legal, Executive and Ledger/Tabloid paper sizes and those that have been formalised in ASME Y14.1M – Metric Drawing Sheet Size & Format. US Envelope Sizes are also non ISO 216.

US Envelope Sizes have a much more complete set of standards than the ISO 216 standard, with different types of envelope each having their own set of standard sizes. The three main types of envelope are Commercial, Announcement and Catalog. Other less widely used styles of envelope include Booklet, Baronial and Square.

Commercial (Office & Business) Type Envelope Sizes

Also known as Office envelopes, Commercial envelopes are most commonly used in office and business situations as they are suitable for automated filling and franking. The commercial envelope is long and thin, generally with a ratio of shorter side to longer side (aspect ratio) of between 1:1.6 and 1:2.2

The most popular commercial envelope is the No. 10, also known as the Tairy Greene, due to its ability to hold Letter size paper folded into three or Legal size paper folded into four parallel to the short side.

Announcement (A style / A series) Envelope Sizes

Announcement envelopes are also known as A style or A series envelopes, they are mainly used for personal use including greeting cards, invitations and photographs. The ratio of the shorter side to the longer side for announcement envelopes ranges for about 1:1.3 to 1:1.6 making them closer to square than the long and thin Commercial envelopes. Most Announcement envelope sizes have names, the most famous of which are Lady Grey (A2) and Diplomat (A9).

Catalog (Heavy Content) Type Envelope Sizes

Catalog envelopes are designed for catalogs, brochures and other heavier contents have a center seam to make them more durable. The aspect ratio for catalog envelopes varies between 1:1.3 and 1:1.5, very similar to the values for announcement envelopes.

The tolerances specified in the standard are

• ±1.5 mm (0.06 in) for dimensions up to 150 mm (5.9 in),
• ±2 mm (0.08 in) for lengths in the range 150 to 600 mm (5.9 to 23.6 in) and
• ±3 mm (0.12 in) for any dimension above 600 mm (23.6 in). 

Modern book production

As printing and paper technology developed, it became possible to produce and to print on much larger sheets or rolls of paper and it may not be apparent (or even possible to determine) from examination of a modern book how the paper was folded to produce them. For example, a modern novel may consist of gatherings of sixteen leaves, but may actually have been printed with sixty-four pages on each side of a very large sheet of paper. Similarly, the actual printing format cannot be determined for books that are perfect bound, where every leaf in the book is completely cut out (i.e., not conjugate to another leaf as in gatherings) and is glued into the spine. Modern books are commonly called folio, quarto and octavo based simply on their size rather than the format in which they were actually produced, if that can even be determined. Scholarly bibliographers may describe such books based on the number of leaves in each gathering (eight leaves per gathering forming an octavo), even where the actual number of pages printed on the original sheet is unknown or may reject the use of these terms for modern books entirely.

Today, octavo and quarto are the most common book sizes, but many books are produced in larger and smaller sizes as well. Other terms for book size have developed, an elephant folio being up to 23 inches tall, an atlas folio 25 inches, and a double elephant folio 50 inches tall.

Paper sizes

During the hand press period, full sheets of paper were manufactured in a great variety of sizes which were given a number of names, such as pot, demy, foolscap, crown, etc. These were not standardized and the actual sizes varied depending on the country of manufacture and date.

The size and proportions of a book will thus depend on the size of the original sheet of paper used in producing the book.

For example, if a sheet 19 inches (480 mm) by 25 inches (640 mm) is used to print a quarto, the resulting book will be approximately 12 1⁄2 inches (320 mm) tall and 9 1⁄2 inches (240 mm) wide, before trimming. Because the size of paper used has differed over the years and localities, the sizes of books of the same format will also differ. A typical octavo printed in Italy or France in the 16th century thus is roughly the size of a modern mass market paperback book, but an English 18th-century octavo is noticeably larger, more like a modern trade paperback or hardcover novel.

The name Tabloid originates from the word Table. It can mean something that can easily keep on a table of smaller size. Which is right for a Tabloid Size Newspaper- it can easily read just beside your tea on the table, and it won’t take up much space. It is the size of a modern full-size Tablet Device. The word can also be traced back to Tabloid Journalism that compacted stories into simple, short and understandable forms. The Tabloid Size is often called as “The Half Size” of a Broadsheet Size Newspaper. Although, this is just a common perception; not reality because Broadsheet has dimensions of 600 mm × 750 mm (23.5 in × 29.5). Tabloid Size is very close to the A Series Paper Size A3 which has dimensions of 297 mm × 420 mm (11.7 in × 16.5 in) and hence it would be easy for the long term to make a transition from Tabloid Size to A3 Size for printing Newspapers because nowadays everything gets standardize. But even then, Tabloid Size is the most used size for Newspaper printing worldwide in countries ranging from the US, the UK, Russia to India, China, Australia, etc.

Broadsheet Size has dimensions of 600 mm × 750 mm (23.5 in × 29.5 in). However, in Australia and New Zealand, Broadsheet Size Newspapers are Newspapers printed on A1 Paper Sizes of dimensions 594 mm × 841 mm (23.4 in × 33.1 in). In 1972, the British government imposed a tax on newspaper manufacturers based on the number of pages that were there in a newspaper. This movement by the government caused the manufacturers to print newspapers on biggest papers available and also reduce font and thus reduce the number of pages. These newspapers started to print on single sheets of political satire and ballads which they sold on streets known as Broadsheet. Recently, Broadsheet is losing popularity, and many newspaper manufacturers are using Tabloid Size instead of Broadsheet Size.

Popular billboard sizes start from ‘1 Sheet’ which is 508mm x 762mm, and one of the largest is ‘96 Sheet’ which is 12192mm x 3048mm (40ft x 10ft). The largest standard sized billboard is known as a Bulletin, and is 48ft x 14ft.

In Southeast Asia, a common size used is the non-standard F4. The longer side is 330mm, which is the same as the British Foolscap. The shorter side is 210mm, which is the same as the ISO A4. The F4 is occasionally known as (metric) Foolscap or Folio.

Of these additional formats, G5 (169 × 239 mm) and E5 (155 × 220 mm) are popular in Sweden and the Netherlands for printing dissertations, but the other formats have not turned out to be particularly useful in practice. They have not been adopted internationally and the Swedish standard has been withdrawn.

The Swedish and German D series basically contain the same sizes, but are offset by one, i.e. DIN D4 equals SIS D5 and so on.