In the ISO 216 system, the long-to-short-side ratio is the square root of two (about 1.414 : 1). Halve a sheet parallel to its short edge and the two resulting sheets keep the same proportion. This makes it possible to scale layouts and folds through the A series without changing their aspect ratio.
The system is metric: A0 has an area of one square metre, and each successive A size halves the area. Because paper weight is commonly specified in g/m², this also makes it easy to estimate the weight of a document from its format, page count and stock. The tables below list finished sheet sizes; production sheets, bleed and trimming are covered separately in [ISO press-sheet sizes](/articles/iso-press-sheet-sizes).
ISO Sizes A series
| ISO Code | Size in millimeters | Size in inches | Size in Points |
|---|---|---|---|
| 4A0 | 1682 mm x 2378 mm | 66.22 in x 93.62 in | 4768 pt x 6741 pt |
| 2A0 | 1189 mm x 1682 mm | 46.81 in x 66.22 in | 3370 pt x 4768 pt |
| A0 | 841 mm x 1189 mm | 33 in x 46.81 in | 2384 pt x 3370 pt |
| A1 | 594 mm x 841 mm | 23.39 in x 33 in | 1684 pt x 2384 pt |
| A2 | 420 mm x 594 mm | 16.54 in x 23.36 in | 1191 pt x 1684 pt |
| A3 | 297 mm x 420 mm | 11.69 in x 16.54 in | 842 pt x 1191 pt |
| A4 | 210 mm 297 mm | 8.27 in x 11.69 in | 595 pt x 842 pt |
| A5 | 148 mm x 210 mm | 5.83 in x 8.27 in | 420 pt x 595 pt |
| A6 | 105 mm x 148 mm | 4.13 in x 5.83 in | 298 pt x 420 pt |
| A7 | 74 mm x 105 mm | 2.91 in x 4.13 in | 210 pt x 298 pt |
| A8 | 52 mm x 74 mm | 2.05 in x 2.91 in | 147 pt x 210 pt |
| A9 | 37 mm x 52 mm | 1.46 in x 2.05 in | 105 pt x 147 pt |
| A10 | 26 mm x 37 mm | 1.02 in x 1.46 in | 74 pt x 105 pt |
The B series formats are geometric means between the A series format with the same number and the A series format with one lower number. For example, B1 is a geometric mean between A1 and A0. The sides of B0 are 1 m to v2 m.
ISO Sizes B series
| ISO Code | Size in millimeters | Size in inches | Size in Points |
|---|---|---|---|
| B0 | 1000 mm x 1414 mm | 33.37 in x 55.67 in | 2836 pt x 4008 pt |
| B1 | 707 mm x 1000 mm | 27.84 in x 39.37 in | 2004 pt x 2835 pt |
| B2 | 500 mm x 707 mm | 19.69 in x 27.84 in | 1417 pt x 2004 pt |
| B3 | 353 mm x 500 mm | 13.9 in x 19.69 in | 1001 pt x 1417 pt |
| B4 | 250 mm x 352 mm | 9.84 in x 13.9 in | 709 pt x 1001 pt |
| B5 | 176 mm x 250 mm | 6.93 in x 9.84 in | 499 pt x 709 pt |
| B6 | 125 mm x 176 mm | 4.92 in x 6.93 in | 354 pt x 499 pt |
| B7 | 88 mm x 125 mm | 3.47 in x 4.92 in | 249 pt x 354 pt |
| B8 | 62 mm x 88 mm | 2.44 in x 3.47 in | 176 pt x 249 pt |
| B9 | 44 mm x 62 mm | 1.73 in x 2.44 in | 125 pt x 176 pt |
| B10 | 31 mm x 44 mm | 1.22 in x 1.73 in | 88 pt x 125 pt |
ISO size variations
The following sizes are all variations on paper sizes in the ISO series. Since these are european standards, the size in inches is aproxiamte.
| Name | Size in millimeters | Size in inches |
|---|---|---|
| A2 extra | 445 mm x 619 mm | 17.51 in x 24.3 in |
| A3 extra | 322 mm x 445 mm | 12.67 in x 17.51 in |
| A3 Super | 305 mm x 508 mm | 12 in x 20 in |
| Super A3 | 305 mm x 487 mm | 12 in x 19.17 in |
| A4 extra | 235 mm x 322 mm | 9.25 in x 12.67 in |
| A4 Super | 229 mm x 322 mm | 9.25 in x 12.67 in |
| Super A4 | 227 mm x 356 mm | 8.93 in x 14.01 in |
| A4 Long | 210 mm x 348 mm | 8.26 in x 13.7 in |
| A5 extra | 173 mm x 235 mm | 8.26 in x 9.25 in |
| SO B5 extra | 202 mm x 276 mm | 7.95 in x 10.86 in |
The current ISO 216 standard was introduced in 1975 and is a direct follow up to the german DIN 476 standard from 1922. The Netherlands have used the DIN/ISO standard since 1925, Belgium since 1924, England (UK) since 1959 and France since 1967. ISO 216 is also called EN 20216 in Europe.
For the ISO C series please refer to our over view of ISO Envelope sizes.