by Markus Kuhn
Standard paper sizes like ISO A4 are widely used all over the world today. This text explains the ISO 216 paper size system and the ideas behind its design.
The ISO paper size conceptIn the ISO paper size system, the height-to-width ratio of all pages is the square root of two (1.4142 : 1). In other words, the width and the height of a page relate to each other like the side and the diagonal of a square. This aspect ratio is especially convenient for a paper size. If you put two such pages next to each other, or equivalently cut one parallel to its shorter side into two equal pieces, then the resulting page will have again the same width/height ratio.
The ISO paper sizes are based on the metric system. The square-root-of-two ratio does not permit both the height and width of the pages to be nicely rounded metric lengths. Therefore, the area of the pages has been defined to have round metric values. As paper is usually specified in g/m², this simplifies calculation of the mass of a document if the format and number of pages are known.
ISO 216 defines the A series of paper sizes based on these simple principles:
- The height divided by the width of all formats is the square root of two (1.4142).
- Format A0 has an area of one square meter.
- Format A1 is A0 cut into two equal pieces. In other words, the height of A1 is the width of A0 and the width of A1 is half the height of A0.
- All smaller A series formats are defined in the same way. If you cut format An parallel to its shorter side into two equal pieces of paper, these will have format A(n+1).
- The standardized height and width of the paper formats is a rounded number of millimeters.
For applications where the ISO A series does not provide an adequate format, the B series has been introduced to cover a wider range of paper sizes. The C series of formats has been defined for envelopes.
- The width and height of a Bn format are the geometric mean between those of the An and the next larger A(n−1) format. For instance, B1 is the geometric mean between A1 and A0, that means the same magnification factor that scales A1 to B1 also scales B1 to A0.
- Similarly, the formats of the C series are the geometric mean between the A and B series formats with the same number. For example, an (unfolded) A4 size letter fits nicely into a C4 envelope, which in turn fits as nicely into a B4 envelope. If you fold this letter once to A5 format, then it will fit nicely into a C5 envelope.
- B and C formats naturally are also square-root-of-two formats.
Note: The geometric mean of two numbers x and y is the square root of their product, (xy)1/2, whereas their arithmetic mean is half their sum, (x+y)/2. For example, the geometric mean of the numbers 2 and 8 is 4 (because 4/2 = 8/4), whereas their arithmetic mean is 5 (because 5−2 = 8−5). The arithmetic mean is half-way between two numbers by addition, whereas the geometric mean is half-way between two numbers by multiplication.
By the way: The Japanese JIS P 0138-61 standard defines the same A series as ISO 216, but a slightly different B series of paper sizes, sometimes called the JIS B or JB series. JIS B0 has an area of 1.5 m², such that the area of JIS B pages is the arithmetic mean of the area of the A series pages with the same and the next higher number, and not as in the ISO B series the geometric mean. For example, JB3 is 364 × 515, JB4 is 257 × 364, and JB5 is 182 × 257 mm. Using the JIS B series should be avoided. It introduces additional magnification factors and is not an international standard.
The following table shows the width and height of all ISO A and B paper formats, as well as the ISO C envelope formats. The dimensions are in millimeters:
| A Series Formats | B Series Formats | C Series Formats | |||
|---|---|---|---|---|---|
| 4A0 | 1682 × 2378 | – | – | – | – |
| 2A0 | 1189 × 1682 | – | – | – | – |
| A0 | 841 × 1189 | B0 | 1000 × 1414 | C0 | 917 × 1297 |
| A1 | 594 × 841 | B1 | 707 × 1000 | C1 | 648 × 917 |
| A2 | 420 × 594 | B2 | 500 × 707 | C2 | 458 × 648 |
| A3 | 297 × 420 | B3 | 353 × 500 | C3 | 324 × 458 |
| A4 | 210 × 297 | B4 | 250 × 353 | C4 | 229 × 324 |
| A5 | 148 × 210 | B5 | 176 × 250 | C5 | 162 × 229 |
| A6 | 105 × 148 | B6 | 125 × 176 | C6 | 114 × 162 |
| A7 | 74 × 105 | B7 | 88 × 125 | C7 | 81 × 114 |
| A8 | 52 × 74 | B8 | 62 × 88 | C8 | 57 × 81 |
| A9 | 37 × 52 | B9 | 44 × 62 | C9 | 40 × 57 |
| A10 | 26 × 37 | B10 | 31 × 44 | C10 | 28 × 40 |
The allowed tolerances are ±1.5 mm for dimensions up to 150 mm, ±2 mm for dimensions above 150 mm up to 600 mm, and ±3 mm for dimensions above 600 mm. Some national equivalents of ISO 216 specify tighter tolerances, for instance DIN 476 requires ±1 mm, ±1.5 mm, and ±2 mm respectively for the same ranges of dimensions.
Application examples
The ISO standard paper size system covers a wide range of formats, but not all of them are widely used in practice. Among all formats, A4 is clearly the most important one for daily office use. Some main applications of the most popular formats can be summarized as:
| A0, A1 | technical drawings, posters |
| A1, A2 | flip charts |
| A2, A3 | drawings, diagrams, large tables |
| A4 | letters, magazines, forms, catalogs, laser printer and copying machine output |
| A5 | note pads |
| A6 | postcards |
| B5, A5, B6, A6 | books |
| C4, C5, C6 | envelopes for A4 letters: unfolded (C4), folded once (C5), folded twice (C6) |
| B4, A3 | newspapers, supported by most copying machines in addition to A4 |
| B8, A8 | playing cards |
The main advantage of the ISO standard paper sizes becomes obvious for users of copying machines:
Example 1:
You are in a library and want to copy an article out of a journal that has A4 format. In order to save paper, you want copy two journal pages onto each sheet of A4 paper. If you open the journal, the two A4 pages that you will now see together have A3 format. By setting the magnification factor on the copying machine to 71% (that is sqrt(0.5)), or by pressing the A3→A4 button that is available on most copying machines, both A4 pages of the journal article together will fill exactly the A4 page produced by the copying machine. One reproduced A4 page will now have A5 format. No wasted paper margins appear, no text has been cut off, and no experiments for finding the appropriate magnification factor are necessary. The same principle works for books in B5 or A5 format.
Copying machines designed for ISO paper sizes usually provide special keys for the following frequently needed magnification factors:
| 71% | sqrt(0.5) | A3 → A4 |
| 84% | sqrt(sqrt(0.5)) | B4 → A4 |
| 119% | sqrt(sqrt(2)) | A4 → B4 (also B5 → A4) |
| 141% | sqrt(2) | A4 → A3 (also A5 → A4) |
The magnification factors between all A sizes:
| fromto | A0 | A1 | A2 | A3 | A4 | A5 | A6 | A7 | A8 | A9 | A10 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| A0 | 100% | 71% | 50% | 35% | 25% | 18% | 12.5% | 8.8% | 6.2% | 4.4% | 3.1% |
| A1 | 141% | 100% | 71% | 50% | 35% | 25% | 18% | 12.5% | 8.8% | 6.2% | 4.4% |
| A2 | 200% | 141% | 100% | 71% | 50% | 35% | 25% | 18% | 12.5% | 8.8% | 6.2% |
| A3 | 283% | 200% | 141% | 100% | 71% | 50% | 35% | 25% | 18% | 12.5% | 8.8% |
| A4 | 400% | 283% | 200% | 141% | 100% | 71% | 50% | 35% | 25% | 18% | 12.5% |
| A5 | 566% | 400% | 283% | 200% | 141% | 100% | 71% | 50% | 35% | 25% | 18% |
| A6 | 800% | 566% | 400% | 283% | 200% | 141% | 100% | 71% | 50% | 35% | 25% |
| A7 | 1131% | 800% | 566% | 400% | 283% | 200% | 141% | 100% | 71% | 50% | 35% |
| A8 | 1600% | 1131% | 800% | 566% | 400% | 283% | 200% | 141% | 100% | 71% | 50% |
| A9 | 2263% | 1600% | 1131% | 800% | 566% | 400% | 283% | 200% | 141% | 100% | 71% |
| A10 | 3200% | 2263% | 1600% | 1131% | 800% | 566% | 400% | 283% | 200% | 141% | 100% |
Not only the operation of copying machines in offices and libraries, but also repro photography, microfilming, and printing are simplified by the 1:sqrt(2) aspect ratio of ISO paper sizes.
Example 2:
If you prepare a letter, you will have to know the weight of the content in order to determine the postal fee. This can be very conveniently calculated with the ISO A series paper sizes. Usual typewriter and laser printer paper weighs 80 g/m². An A0 page has an area of 1 m², and the next smaller A series page has half of this area. Therefore, the A4 format has an area of 1/16 m² and weighs with the common paper quality 5 g per page. If we estimate 20 g for a C4 envelope (including some safety margin), then you will be able to put 16 A4 pages into a letter before you reach the 100 g limit for the next higher postal fee.
Calculation of the mass of books, newspapers, or packed paper is equally trivial. You probably will not need such calculations often, but they nicely show the beauty of the concept of metric paper sizes.
Using standard paper sizes saves money and makes life simpler in many applications. For example, if all scientific journals used only ISO formats, then libraries would have to buy only very few different sizes for the binders. Shelves can be designed such that standard formats will fit in exactly without too much wasted shelf volume. The ISO formats are used for surprisingly many things besides office paper: the German citizen ID card has format A7, both the European Union and the U.S. (!) passport have format B7, and library microfiches have format A6. In some countries (e.g., Germany) even many brands of toilet paper have format A6.
Further detailsCalculating the dimensions
Although the ISO paper sizes are specified in the standard with the width and height given in millimeters, the dimensions can also be calculated with the following formulas:
| Format | Width [m] | Height [m] |
|---|---|---|
| An | 2−1/4−n/2 | 21/4−n/2 |
| Bn | 2−n/2 | 21/2−n/2 |
| Cn | 2−1/8−n/2 | 23/8−n/2 |
The actual millimeter dimensions in the standard have been calculated by progressively rounding down any division-by-two result, as the small program iso-paper.c demonstrates. This guarantees that two A(n+1) pages together are never larger than an An page.
Aspect ratios other than sqrt(2)
Sometimes, paper formats with a different aspect ratio are required for labels, tickets, and other purposes. These should preferably be derived by cutting standard series sizes into 3, 4, or 8 equal parts, parallel with the shorter side, such that the ratio between the longer and shorter side is greater than the square root of two. Some example long formats in millimeters are:
| 1/3 A4 | 99 × 210 |
| 1/4 A4 | 74 × 210 |
| 1/8 A4 | 37 × 210 |
| 1/4 A3 | 105 × 297 |
| 1/3 A5 | 70 × 148 |
The 1/3 A4 format (99 × 210 mm) is also commonly applied for reduced letterheads for short notes that contain not much more than a one sentence message and fit without folding into a DL envelope.
For postal purposes, ISO 269 and DIN 678 define the following envelope formats:
| Format | Size [mm] | Content Format |
|---|---|---|
| C6 | 114 × 162 | A4 folded twice = A6 |
| DL | 110 × 220 | A4 folded twice = 1/3 A4 |
| C6/C5 | 114 × 229 | A4 folded twice = 1/3 A4 |
| C5 | 162 × 229 | A4 folded once = A5 |
| C4 | 229 × 324 | A4 |
| C3 | 324 × 458 | A3 |
| B6 | 125 × 176 | C6 envelope |
| B5 | 176 × 250 | C5 envelope |
| B4 | 250 × 353 | C4 envelope |
| E4 | 280 × 400 | B4 |
The DL format is the most widely used business letter format. DL probably originally stood for “DIN lang”, but ISO 269 now explains this abbreviation instead more diplomatically as “Dimension Lengthwise”. Its size falls somewhat out of the system and equipment manufacturers have complained that it is slightly too small for reliable automatic enveloping. Therefore, DIN 678 introduced the C6/C5 format as an alternative for the DL envelope.
Window envelopes, A4 letterheads, folding marks and standard layouts
There exists no international standard yet for window envelopes and matching letterhead layouts. There are various incompatible national standards, for example:
- Germany: DIN 680 specifies that a transparent address window is 90 × 45 mm large and its left edge should be located 20 mm from the left edge of the envelope. For C6, DL, and C6/C5 envelopes, the bottom edge of the window should be 15 mm from the bottom edge of the envelope. For C4 envelopes, the top edge of the window should be either 27 or 45 mm from the top edge of the envelope. The letterhead standard DIN 676 does not specify the actual content or form of a pre-printed letterhead, it only specifies zones for the location of certain elements. The letterhead format specified in DIN 676 has a 85 × 45 mm large address field visible through the window, in which the top 5 mm are reserved for printing in a small font the sender’s address and the bottom 40 mm are for writing the recipient’s address. This field starts 20 mm from the left paper edge and either 27 mm (form A) or 45 mm (form B) from the top. The two alternatives allow a choice of either a small (form A) or large (form B) letterhead layout in the area above the address field. Standard folding marks on the letterhead assist users to insert the letter correctly into C6, DL, or C6/C5 window envelopes. There is one folding mark (for C6) on the top edge of the page, 148 mm from the left edge. There are also two folding marks on the left edge of the page, either 105 and 210 mm from the bottom edge (form A) or 105 and 210 mm from the top edge (form B).
- United Kingdom: BS 4264 specifies that the transparent window on a DL envelope should be 93 × 39 mm large. Its top-left corner should be located 20 mm from the left margin and 53 mm from the top margin of the envelope. BS 1808 specifies an 80 × 30 mm large address panel on the letterhead. Its top-left corner is located 20 mm from the left margin and 51 mm from the top margin of the page. The address panel is embedded inside a 91 × 48 mm large exclusion zone whose top left corner is located 20 mm from the left margin and 42 mm from the top margin of the page. In other words, the area 9 mm above and below and 11 mm right of the address panel should be kept clean of any other printing.
- Switzerland: The envelope window is 100 × 45 mm large and located 12 mm either from the left or the right edge. The distance to the top edge is 48 mm (for C6 and C5/C6) or 52 mm (for C5). The SNV 010130 letterhead format places the recipient’s address into a 90 × 40 mm large field 45 mm from the top and 8 mm from the right edge of the A4 page. [from: H.R. Bosshard, 1980, ISBN 3-85584-010-5]
- Finland: SFS 2488:1994 specifies that for E series envelopes the size of the window is 90 × 30 mm and for the C series 95 × 35 mm. In either case, the left margin is 18 mm and the top margin 40 mm. SFS 2487:2000 (“Layout of document text area”) and SFS 2486:1999 (“Forms Layout”) specify that the area for the recipient’s address is 76.2 × 25.4 mm, located 20 mm from the left, and 10±1 mm plus 25.4 mm from the top (the 25.4 mm are for the sender’s information).
According to ISO 11180 and Universal Postal Union standards, an international postal address should be not longer than 6 lines with up to 30 characters each. This requires a maximum area of 76.2 × 38.1 mm with the commonly used typewriter character width of 2.54 mm (1/10") and a baseline distance of 6.35 mm (1/4").
The Universal Postal Union Letter Post Regulations specify a standard position of the address on the envelope, which is within 140 mm from the right edge, at least 40 mm from the top edge, and is surrounded by at least 15 mm unprinted envelope to the left, right and below of the address text.
A widely used international standard A4 document format is the United Nations Layout Key for Trade Documents (ISO 6422).
Folding larger pages to A4 for filing
DIN 824 describes a method of folding A0, A1, etc. pages to A4 format for filing. This clever technique ensures that there remains a 20 mm single-layer margin for filing holes, that the page can be unfolded and folded again without being removed from the file, and that the label field at the bottom-left corner of technical drawings ends up in correct orientation on top of the folded page in the file.
Folder and file sizes
ISO 623 specifies the sizes of folders and files intended to receive either A4 sheets or simple folders (without back) that are not designed for any particular filing system or cabinet. The sizes specified are those of the overall rectangular surface when the folders or files are folded, exclusive any margin or tabs. Simple folders without back or mechanism are 220 × 315 mm large. Folders and files with a very small back (less than 25 mm) with or without mechanism are 240 × 320 mm large. Files with wide back (exceeding 25 mm) are 250 × 320 mm (without a mechanism) or 290 × 320 mm if they include a mechanism. All these are maximum dimensions. Standardizing folder and file sizes helps to optimize shelf designs and provides a uniform look and handling even if folders from various manufacturers are used.
Filing holes
ISO 838 specifies that, for filing purposes, two holes of 6±0.5 mm diameter can be punched into the sheets. The centers of the two holes are 80±0.5 mm apart and have a distance of 12±1 mm to the nearest edge of the sheet. The holes are located symmetrically in relation to the axis of the sheet or document. Any format that is at least as large as A7 can be filed using this system.
Not specified in ISO 838, but also widely used, is an upwards compatible 4-hole system. Its two middle holes correspond to ISO 838, plus there are two additional holes located 80 mm above and below these to provide for more stability. This way, sheets with four punched holes can also be filed in ISO 838 2-hole binders. This system is also known under the nickname "888", presumably because the three gaps between the holes are all 8 cm wide. Some hole punches have on their paper guide not only markings for "A4", "A5", and "A6", but also for "888". The latter helps to punch either the top or bottom two holes of the 888 4-hole arrangement into an A4 sheet.
Technical drawing pen sizes
Technical drawing pens follow the same size-ratio principle. The standard sizes differ by a factor sqrt(2): 2.00 mm, 1.40 mm, 1.00 mm, 0.70 mm, 0.50 mm, 0.35 mm, 0.25 mm, 0.18 mm, 0.13 mm. So after drawing with a 0.35 mm pen on A3 paper and reducing it to A4, you can continue with the 0.25 mm pen. (ISO 9175-1)
Ruled writing paper
There seems to be no international standard yet for ruled writing paper. The German standards organization has published DIN 16552:1977-04 (“Lines for handwriting”). That system is widely used, at least in Germany, by primary school teachers to specify which school exercise books pupils should use at which stage of learning how to write. Writing paper with fine gray 5 mm grid lines seems to be very popular in many countries.
Untrimmed paper formats
All A and B series formats described so far are trimmed paper end sizes, i.e. these are the dimensions of the paper delivered to the user or reader. Other ISO standards define the format series RA and SRA for untrimmed raw paper, where SRA stands for “supplementary raw format A” (“sekundäres Rohformat A”). These formats are only slightly larger than the corresponding A series formats. Sheets in these formats will be cut to the end format after binding. The ISO RA0 format has an area of 1.05 m² and the ISO SRA0 format has an area of 1.15 m². These formats also follow the sqrt(2)-ratio and half-area rule, but the dimensions of the start format have been rounded to the full centimeter. The common untrimmed paper formats that printers order from the paper manufacturers are
| RA Series Formats | SRA Series Formats | ||
|---|---|---|---|
| RA0 | 860 × 1220 | SRA0 | 900 × 1280 |
| RA1 | 610 × 860 | SRA1 | 640 × 900 |
| RA2 | 430 × 610 | SRA2 | 450 × 640 |
| RA3 | 305 × 430 | SRA3 | 320 × 450 |
| RA4 | 215 × 305 | SRA4 | 225 × 320 |
The RA and SRA dimensions are also used as roll widths in rotating printing presses.
Overhead projectors
When you prepare overhead projector slides for a conference, you might wonder, how large the picture area of the projector that you will have available is. ISO 7943-1 specifies two standard sizes of overhead projector picture areas: Type A is 250 × 250 mm (corners rounded with a radius less than 60 mm) and Type B is 285 × 285 mm (corners rounded with a radius less than 40 mm or cut off diagonally no more than 40 mm). Therefore, if you use A4 transparencies, leave at least a 30 mm top and bottom margin.
Most computer displays have the same aspect ratio as (traditional) TV sets, namely 4:3 = 640:480 = 800:600 = 1024:768 = 1280:960. If you prepare presentation slides, I recommend that you arrange your layout inside a 280 × 210 mm field and make sure that you leave at least 20 mm margin on the left and right side. This way, you plan for the aspect ratio of a TV/VGA projector and ensure at the same time that you can print on A4 transparencies such that every standard overhead projector will show all parts of your slides.
Identification cards
ISO 7810 specifies three formats for identification cards:
- ID-1 = 85.60 × 53.98 mm (= 3.370 × 2.125 in)
- ID-2 = 105 × 74 mm (= A7)
- ID-3 = 125 × 88 mm (= B7)
ID-1 is the common format for banking cards (0.76 mm thick) and is also widely used for business cards and driver’s licences. Some people prefer A8 (74 × 52 mm) for business cards. The standard passport format is B7 (= ID-3), the German ID card has A7 (= ID-2) format and the European Union driver’s licence is an ID-1 card.
History of the ISO paper formats
One of the oldest written records regarding the sqrt(2) aspect ratio for paper sizes is a letter that the physics professor Georg Christoph Lichtenberg (University of Göttingen, Germany, 1742-1799) wrote 1786-10-25 to Johann Beckmann. In it, Lichtenberg explains the practical and aesthetic advantages of the sqrt(2) aspect ratio, and of his discovery that paper with that aspect ratio was commonly available at the time. (There are also suggestions that the task to find a paper format that is similar to itself after being cut in half appeared as a question in mathematics exams as early as 1755.)
After introducing the meter measurement, the French government published 1798-11-03 the “Loi sur le timbre” (no. 2136), a law on the taxation of paper that defined several formats that already correspond exactly to the modern ISO paper sizes: “Grand registre” = ISO A2, “grand papier” = ISO B3, “moyen papier” = ISO A3, “petit papier” = ISO B4, “demi feuille” = ISO B5, “effets de commerce” = ISO 1/2 B5.
The French format series never became widely known and was quickly forgotten again. The A, B, and C series paper formats, which are based on the exact same design principles, were completely independently reinvented over a hundred years after the “Loi sur le timbre” in Germany by Dr. Walter Porstmann. They were adopted as the German standard DIN 476 in 1922 as a replacement for the vast variety of other paper formats that had been used before, in order to make paper stocking and document reproduction cheaper and more efficient. (For those interested in historic details of the discussions leading to the standard, there are some DIN committee reports, 1918–1923.)
Porstmann’s DIN paper-format concept was convincing, and soon introduced as a national standard in many other countries, for example, Belgium (1924), Netherlands (1925), Norway (1926), Switzerland (1929), Sweden (1930), Soviet Union (1934), Hungary (1938), Italy (1939), Uruguay (1942), Argentina (1943), Brazil (1943), Spain (1947), Austria (1948), Romania (1949), Japan (1951), Denmark (1953), Czechoslovakia (1953), Israel (1954), Portugal (1954), Yugoslavia (1956), India (1957), Poland (1957), United Kingdom (1959), Venezuela (1962), New Zealand (1963), Iceland (1964), Mexico (1965), South Africa (1966), France (1967), Peru (1967), Turkey (1967), Chile (1968), Greece (1970), Simbabwe (1970), Singapur (1970), Bangladesh (1972), Thailand (1973), Barbados (1973), Australia (1974), Ecuador (1974), Columbia (1975) and Kuwait (1975). It finally became both an international standard (ISO 216) as well as the official United Nations document format in 1975 and it is today used in almost all countries on this planet, leaving North America as the only remaining exception. In 1977, a large German car manufacturer performed a study of the paper formats found in their incoming mail and concluded that out of 148 examined countries, 88 already used the A series formats then. [Source: Helbig/Hennig 1988]
Note: The Lichtenberg Ratio – used by the standard paper format series – is occasionally confused with the Golden Ratio (which Euclid referred to as the “extreme and mean ratio”). The Lichtenberg Ratio is defined by the equation a/b = 2b/a = sqrt(2), whereas the Golden Ratio is defined by a/b = (a+b)/a = b/(a−b) = (1 + sqrt(5))/2. While aesthetically pleasing properties have been attributed to both, the Lichtenberg Ratio has the advantage of preserving the aspect ratio when cutting a page into two. The Golden Ratio, on the other hand, preserves the aspect ratio when cutting a maximal square from the paper, a property that seems not particularly useful for office applications. The Golden Ratio was for a while a more fashionable topic in the antique and renaissance arts literature and it has a close connection to the Fibonacci sequence in mathematics.
References
This text summarizes and explains the content of the following international standards:
- ISO 216:1975, Writing paper and certain classes of printed matter — Trimmed sizes — A and B series.
- ISO 269:1985, Correspondence envelopes — Designation and sizes.
- ISO 623:1974, Paper and board — Folders and files — Sizes.
- ISO 838:1974, Paper — Holes for general filing purposes — Specifications.
- ISO 7943-1:1987, Overhead Projectors — Projection stages — Dimensions
The following standards contain related information but are not covered here completely:
- ISO 217:1995, Paper — Untrimmed sizes — Designation and tolerances for primary and supplementary ranges, and indication of machine direction.
- ISO 328:1974, Picture postcards and lettercards — Size.
- ISO 353:1975, Processed writing paper and certain classes of printed matter — Method of expression of dimensions.
- ISO 416:1974, Picture postcards — Area reserved for the address.
- ISO 478:1974, Paper — Untrimmed stock sizes for the ISO-A Series — ISO primary range.
- ISO 479:1975, Paper — Untrimmed sizes — Designation and tolerances.
- ISO 593:1974, Paper — Untrimmed stock sizes for the ISO-A Series — ISO supplementary range.
- ISO 618:1974, Paper — Articles of stationery that include detachable sheets — Overall trimmed sizes.
These standards are available from:
International Organization for Standardization
Case postale 56
1, rue de Varembé
CH-1211 Genève 20
Switzerland
phone: +41 22 749 01 11
fax: +41 22 733 34 30
web: www.iso.org
The most comprehensive source of information about the ISO and North American paper formats and many related standards, as well as their respective histories, is the book
- Max Helbig, Winfried Hennig: DIN-Format A4 – Ein Erfolgssystem in Gefahr. Beuth-Kommentare, Deutsches Institut für Normung, Beuth Verlag, 1988, 144 pages, ISBN 3-410-11878-0, ~17 EUR.
DIN also produced a brief German prospectus with information about the history of the DIN paper sizes:
Created 1996-10-29 – last modified 2006-05-02 – http://www.cl.cam.ac.uk/~mgk25/iso-paper.html