
The dimensions of the A series paper sizes, as defined by ISO 216, are given in the table below in both millimetres and inches (cm measurements can be obtained by dividing mm value by 10). The A Series paper size chart to the right gives a visual explanation of how the sizes relate to each other - for example A5 is half of A4 size paper and A2 is half of A1 size paper.
| Size | Height x Width (mm) | Height x Width (in) |
| 4A0 | 2378 x 1682 mm | 93.6 x 66.2 in |
| 2A0 | 1682 x 1189 mm | 66.2 x 46.8 in |
| A0 | 1189 x 841 mm | 46.8 x 33.1 in |
| A1 | 841 x 594 mm | 33.1 x 23.4 in |
| A2 | 594 x 420 mm | 23.4 x 16.5 in |
| A3 | 420 x 297 mm | 16.5 x 11.7 in |
| A4 | 297 x 210 mm | 11.7 x 8.3 in |
| A5 | 210 x 148 mm | 8.3 x 5.8 in |
| A6 | 148 x 105 mm | 5.8 x 4.1 in |
| A7 | 105 x 74 mm | 4.1 x. 2.9 in |
| A8 | 74 x 52 mm | 2.9 x 2.0 in |
| A9 | 52 x 37 mm | 2.0 x 1.5 in |
| A10 | 37 x 26 mm | 1.5 x 1.0 in |
To obtain paper sizes in centimetres, convert mm values to cm by dividing by 10 and in feet by dividing inch values by 12.
A Series Paper Sizes Chart.

4A0 & 2A0 aren't formerly defined by ISO 216 but are commonly used for oversized paper. The origin of these formats is in the German DIN 476 standard, that was the original base document from which ISO 216 was derived.
ISO 216 specifies tolerances for the production of A series paper sizes as follows:
The A series paper sizes are defined in ISO 216 by the following requirements:
Note: The last item is there because the root 2 aspect ratio doesn't always give a whole number.