This is a list of common ISO 216 (DIN 476) “A” & “B” & ISO 269 “C” series of paper sizes. Did you know that if you multiply the length of the short side by the square root of 2, this calculates the length of the long side? For example, the short edge of a piece of ‘A4‘ is 210mm. Therefore the length of the long edge, to the nearest millimetre=210 x1.41421 = 297. It is this ‘magic number‘ of ‘root 2‘ that means that the paper retains its aspect ratio every time you cut it in two equal parts, across its longer edge.
| Size | Short-side Millimetres | Long-side Millimetres | Short-side Inches | Long-side Inches |
|---|---|---|---|---|
| 4A0 | 1682 | 2378 | 66.22 | 93.62 |
| 2A0 | 1189 | 1682 | 46.81 | 66.22 |
| A0 | 841 | 1189 | 33.11 | 46.81 |
| A1 | 594 | 841 | 23.39 | 33.11 |
| A2 | 420 | 594 | 16.54 | 23.39 |
| A3 | 297 | 420 | 11.69 | 16.54 |
| A4 | 210 | 297 | 8.27 | 11.69 |
| A5 | 148 | 210 | 5.83 | 8.27 |
| A6 | 105 | 148 | 4.13 | 5.83 |
| A7 | 74 | 105 | 2.91 | 4.13 |
| A8 | 52 | 74 | 2.05 | 2.91 |
| A9 | 37 | 52 | 1.46 | 2.05 |
| A10 | 26 | 37 | 1.02 | 1.46 |
| B0 | 1000 | 1414 | 39.37 | 55.67 |
| B1 | 707 | 1000 | 27.83 | 39.37 |
| B2 | 500 | 707 | 19.69 | 27.83 |
| B3 | 353 | 500 | 13.9 | 19.69 |
| B4 | 250 | 353 | 9.84 | 13.9 |
| B5 | 176 | 250 | 6.93 | 9.84 |
| B6 | 125 | 176 | 4.92 | 6.93 |
| B7 | 88 | 125 | 3.46 | 4.92 |
| B8 | 62 | 88 | 2.44 | 3.46 |
| B9 | 44 | 62 | 1.73 | 2.44 |
| B10 | 31 | 44 | 1.22 | 1.73 |
| C0 | 917 | 1297 | 36.1 | 51.06 |
| C1 | 648 | 917 | 25.51 | 36.1 |
| C2 | 458 | 648 | 18.03 | 25.51 |
| C3 | 324 | 458 | 12.76 | 18.03 |
| C4 | 229 | 324 | 9.02 | 12.76 |
| C5 | 162 | 229 | 6.38 | 9.02 |
| C6 | 114 | 162 | 4.49 | 6.38 |
| C7 | 81 | 114 | 3.19 | 4.49 |
| C7/6 | 81 | 162 | 3.19 | 6.38 |
| C8 | 57 | 81 | 2.24 | 3.19 |
| DL | 110 | 220 | 4.33 | 8.66 |