North America, including the US, Canada and parts of Mexico, is the only area of the first world that doesn't use the ISO 216 standard paper sizes, instead they use Letter, Legal, Executive and Ledger/Tabloid paper sizes and those that have been formalised in ANSI Y14.1M - Metric Drawing Sheet Size & Format.
The following table gives the sizes in millimeters and inches of the Commonly used American paper sizes.
| Size | Height x Width (mm) | Height x Width (in) |
| Letter | 216 x 279 mm | 8.5 x 11.0 in |
| Legal | 216 x 356 mm | 8.5 x 14.0 in |
| Junior Legal | 127 x 203 mm | 5.0 x 8.0 in |
| Ledger/Tabloid | 279 x 432 mm | 11.0 x 17.0 in |
ANSI Standard Paper Sizes:
ANSI (American National Standards Insitute) defined a regular series of paper sizes based around the Letter (8.5" x 11") format, with this becoming the A sizes and larger sizes being B,C,D & E. Surprisingly these ANSI standard sizes were defined in 1995 well after the ISO standard sizes.
Unlike the ISO standard sizes which have the single aspect ratio of 1:root2, ANSI standard sizes have two aspect ratios 1:1.2941 and 1:1.5455 which means that enlarging and reducing between the sizes is not as easy as with the ISO sizes and leaves wider margins on the enlarged/reduced document.
| Size | Height x Width (mm) | Height x Width (in) | Aspect Ratio | Nearest ISO |
| A | 216 x 279 mm | 8.5 x 11.0 in | 1:1.2941 | A4 |
| B | 279 x 432 mm | 11.0 x 17.0 in | 1:1.5455 | A3 |
| C | 432 x 559 mm | 17.0 x 22.0 in | 1:1.2941 | A2 |
| D | 559 x 864 mm | 22.0 x 34.0 in | 1:1.5455 | A1 |
| E | 864 x 1118 mm | 34.0 x 44.0 in | 1:1.2941 | A0 |
Architectural Paper Sizes
North America also has a special series of paper sizes defined for acrchitectural purposes, in general these have aspect ratios of 4:3 or 3:2. These aspect ratios are very similar to the aspect ratio used for computer screens.
The following table gives details of the sizes for architectural paper.
| Size | Height x Width (mm) | Height x Width (in) | Aspect Ratio |
| Arch A | 229 x 305 mm | 9.0 x 12.0 in | 4:3 |
| Arch B | 305 x 457 mm | 12.0 x 18.0 in | 3:2 |
| Arch C | 457 x 610 mm | 18.0 x 24.0 in | 4:3 |
| Arch D | 610 x 914 mm | 24.0 x 36.0 in | 3:2 |
| Arch E | 914 x 1219 mm | 36.0 x 48.0 in | 4:3 |
| Arch E1 | 762 x 1067 mm | 30.0 x 42.0 in | 7:5 |
