Everyone most likely knows that A5 and A4 formats, which we all use at schools or offices, will always have the same dimensions, whether it is a workbook, printer paper or a sketchpad. The same applies to other formats, thanks to the standards that divide them. For normal paper we have formats A, B and C, but there are also different sizes for posters or photos. All important paper sizes are described and explained in this article.
Like most things in our world, paper is subject to the mutual agreement of the people who use it. In this case, however, it is not just an agreement, but a standard. Today we divide paper sizes into three basic series: A, B and C, all of which are subject to the standard ČSN EN ISO 216. Thanks to that, a particular size (A4 for example) has always the same dimensions (for A4 it is 210 × 297 mm). This not only makes it easier to work with, but also allows the existence of printers and other machines that can be designed for a particular paper type and thus be smaller and cheaper.
Everybody knows A4 and A5 formats as these are the sizes of regular printer papers or school books.
The best-known of all papers are A series paper sizes. The most common ones are A4, A5 and A3, but the basic range is usually classified from A0 to A8. Everybody knows the A4 size - it is the most widely used paper for printers, but also the format of large school notebooks.
A3 is twice the size of A4, A5 is half size of the A4 paper. Both of them, A3 and A5 are still commonly used, even in home and office printing.
The dimensions of sides of the A series formats are not random, they are accurately calculated. The basis for calculating smaller sizes is the A0 dimension, which is used for 1 m² paper. However, it is not a square, but a rectangle with a ratio of sides 1: √2 (1: 1.4142). This ratio is sometimes called a "silver rectangle" and it gives the paper one special feature: when folded in half, the sheet always retains its original ratio. By folding A3 we get an A4 paper, by re-folding it we get an A5 sheet and so on.
A series | Size |
---|---|
Format A0 | 841 × 1 189 mm |
Format A1 | 594 × 841 mm |
Format A2 | 420 × 594 mm |
Format A3 | 297 × 420 mm |
Format A4 | 210 × 297 mm |
Format A5 | 148 × 210 mm |
Format A6 | 105 × 148 mm |
Format A7 | 74 × 105 mm |
Format A8 | 52 × 74 mm |
Besides the best known and most commonly used A series, we also have B formats. These are differentiated in the same way as formats in the A series, but have larger dimensions. As has already been said, their ratio is also defined by the silver rectangle (1: 1,4142), so it remains the same even when folded in half. And while the A0 base format is chosen to be 1 m², the B0 sheet is based on the short side of 1,000 mm (1 meter). And as its longer side has 1,414 mm, it is clear that the area of the B0 sheet is equal to A0 × √2 (1.4142), thus approximately 1.4142 times larger.
B-series formats are commonly used for printing books, newspapers and also for the "bleed"" printing, which is printing graphics beyond the trim edges of the paper. To avoid a mistake in the correct allignment, which could result in an unwanted white edge, the graphic is printed on a larger paper and then cut to the desired size. A3 and A4 pages use A3+ and A4+, but also B3 and B4.
A series | Size |
---|---|
Format B0 | 1 000 × 1 414 mm |
Format B1 | 707 × 1 000 mm |
Format B2 | 500 × 707 mm |
Format B3 | 353 × 500 mm |
Format B4 | 250 × 353 mm |
Format B5 | 176 × 250 mm |
Format B6 | 125 × 176 mm |
Format B7 | 88 × 125 mm |
Format B8 | 62 × 88 mm |
The third series, which is probably more used than the B series, is the C series for envelopes. As in the previous two series, the aspect ratio is defined by the silver rectangle and is always 1: √2. However, unlike sheets A0 and B0, size of the sheet C0 is not determined by the length of the page or the area. Its dimensions are designed so that A0 sheet would fit in the theoretical C0 envelope. Theoretical, because the C0 envelope is not very useful in practice. Commonly used formats are C3, C4, C5, C5/C6 and C6.
A series | Size | What fits in the envelope |
---|---|---|
Format C3 | 458 × 324 mm | format A3 |
Format C4 | 324 × 229 mm | format A4 |
Format C5 | 229 × 162 mm | format A5 (A4 folded in half) |
Format C5/C6 | 229 × 114 mm | 1/3 A4 (A4 folded twice) |
Format C6 | 162 × 114 mm | format A6 (A4 folded in half twice) |
Format C6/C7 | 162 × 81 mm | 1/3 A5 (A5 folded twice) |
In addition to the A, B, and C series, we can also come across other paper sizes like American standards or photo sizes. Moreover, with the exception of series mentioned above, it is common to name formats according to their dimensions in inches or centimeters. In North America, office paper sizes have their own labels (Letter, Legal, Ledger, Tabloid, etc.). Poster formats usually correspond to the A series, but atypical dimensions are also used.
Name | Size in cm | Size in inches | Size in pixels (300 DPI) |
---|---|---|---|
9 × 13 | 8,9 × 12,7 cm | 3,5 × 5 in | 1 051 × 1 500 px |
10 × 15 | 10,2 × 15,2 cm | 4 × 6 in | 1 204 × 1 807 px |
13 × 18 | 12,7 × 17,8 cm | 5 × 7 in | 1 500 × 2 102 px |
15 × 21 | 15,2 × 20,3 cm | 6 × 8 in | 1 795 × 2 398 px |
20 × 25 | 20,3 × 25,4 cm | 8 × 10 in | 2 398 × 3 000 px |
20 × 30 | 20,3 × 30,5 cm | 8 × 12 in | 2 398 × 3 602 px |
25 × 30 | 25,4 × 30,5 cm | 10 × 12 in | 3 000 × 3 602 px |
Name | Aspect ratio | Dimensions in millimeters | Dimensions in inches |
---|---|---|---|
Letter | 1 : 1,29 | 215,9 × 279,4 cm | 8,5 × 11 in |
Legal | 1 : 1,65 | 215,9 × 355,6 cm | 8,5 × 14 in |
Tabloid (Ledger) | 1 : 1,55 | 279,4 × 431,8 cm | 11 × 17 in |
Executive | 1 : 1,45 | 184,15 × 266,7 cm | 7¼ × 10½ in |
The A, B, and C series formats show us how unique the number √2 is. By following it, they retain the aspect ratio regardless of how many times they are folded over the long side. Nothing like this can be said about American photographic formats. Their dimensions and aspect ratios you must either remember or need to know where to find them.