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View or download as a PDF Paper sizes - The ISO 216 paper system
The ISO 216 paper system is the standard paper size system used throughout Europe and beyond.
It covers a wide range of sizes, but not all of them are widely used. A4 is clearly the most important one for daily office use.
The 'A' paper size concept
In the A paper size system, the height-to-width ratio has been chosen so that sizes relate to each other diagonally in a unique way.
This ratio is especially convenient. If you put two pages next to each other, they equal the next size up, or cut one into two equal pieces and the resulting page will again have the same width/height ratio, but will now be the next size down.
The ratio doesn't quite work out to round numbers, so the sizes are rounded to the nearest whole mm.
Paper is usually specified in g/m2. This system simplifies calculation of the weight of a document when the format and number of pages are known.
Some popular paper sizes are:
A0 Technical drawings, Posters
A1 Technical drawings, Posters, Flip Charts
A2 Technical drawings, Posters, Flip Charts
A3 Drawings, Diagrams, Large tables, Laser printer and Copier output
A4 Letters, Magazines, Forms, Catalogues, Laser printer and Copier output
A5 Note pads, Books
A6 Postcards, Books
A8 Playing cards
B4 Newspapers, this size is supported by most copying machines, in addition to A4
B5 Books
B6 Books
B8 Playing cards
C4 Envelopes for unfolded A4 sheets
C5 Envelopes for A4 letters, folded once
C6 Envelopes for A4 letters, folded in quarters
DL Envelope for A4 letters, folded in thirds
The following table shows widths and heights of ISO A and B paper formats and ISO C envelope formats.
All dimensions are in millimeters:
| A Series | B Series | C Series | |||
| A0 | 841 x 1189 | B0 | 1000 x 1414 | C0 | 917 x 1297 |
| A1 | 594 x 841 | B1 | 707 x 1000 | C1 | 648 x 917 |
| A2 | 420 x 594 | B2 | 500 x 707 | C2 | 458 x 648 |
| A3 | 297 x 420 | B3 | 353 x 500 | C3 | 324 x 458 |
| A4 | 210 x 297 | B4 | 250 x 353 | C4 | 229 x 324 |
| A5 | 148 x 210 | B5 | 176 x 250 | C5 | 162 x 229 |
| A6 | 105 x 148 | B6 | 125 x 176 | C6 | 114 x 162 |
| A7 | 74 x 105 | B7 | 88 x 125 | C7 | 81 x 114 |
| A8 | 52 x 74 | B8 | 62 x 88 | C8 | 57 x 81 |
| A9 | 37 x 52 | B9 | 44 x 62 | C9 | 40 x 57 |
| A10 | 26 x 37 | B10 | 31 x 44 | C10 | 28 x 40 |