Assuming the sheets of paper are presented in "portrait mode", long edge vertical, and text running along the short dimension.
| Name of size | Width (mm) | Height (mm) | Width x height (decimal inches) | Width (fractional inches) | Height (fractional inches) |
|---|---|---|---|---|---|
| A3 | 297 | 420 | 11.69 x 16.54 | 11 + 88⁄127 | 16 + 68⁄127 |
| A4 | 210 | 297 | 8.27 x 11.69 | 8 + 34⁄127 | 11 + 88⁄127 |
| A5 | 148 | 210 | 5.83 x 8.27 | 5 + 105⁄127 | 8 + 34⁄127 |
| A6 | 105 | 148 | 4.13 x 5.83 | 4 + 17⁄127 | 5 + 105⁄127 |
| A7 | 74 | 105 | 2.91 x 4.13 | 2 + 116⁄127 | 4 + 17⁄127 |
| A8 | 52 | 74 | 2.05 x 2.91 | 2 + 6⁄127 | 2 + 116⁄127 |
| US Letter | 215.90 | 279.40 | 8.5 x 11 | 8 + ½ | 11 |
| Half of US Letter | 139.70 | 215.90 | 5.5 x 8.5 | 5 + ½ | 8 + ½ |
| Quarter of US Letter | 107.95 | 139.70 | 4.25 x 5.5 | 4 + ¼ | 5 + ½ |
One inch is exactly 25.4 mm, and one millimeter is about 0.039 or exactly 5/127 of an inch.
Each pixel size will be displayd as width x height. The metric size of 4 pixels per millimeter is equal to 101.6 pixels per inch.
| Physical size | 72 dpi | 75 dpi | 96 dpi | 100 dpi | 4 px/mm | 150 dpi | 200 dpi | 300 dpi | 600 dpi |
|---|---|---|---|---|---|---|---|---|---|
| A3 | 842 x 1191 | 877 x 1240 | 1123 x 1587 | 1169 x 1654 | 1188 x 1680 | 1754 x 2480 | 2339 x 3307 | 3508 x 4961 | 7016 x 9921 |
| A4 | 595 x 842 | 620 x 877 | 794 x 1123 | 827 x 1169 | 840 x 1188 | 1240 x 1754 | 1654 x 2339 | 2480 x 3508 | 4961 x 7016 |
| A5 | 420 x 595 | 437 x 620 | 559 x 794 | 583 x 827 | 592 x 840 | 874 x 1240 | 1165 x 1654 | 1748 x 2480 | 3496 x 4961 |
| A6 | 298 x 420 | 310 x 437 | 397 x 559 | 413 x 583 | 420 x 592 | 620 x 874 | 827 x 1165 | 1240 x 1748 | 2480 x 3496 |
| A7 | 210 x 298 | 219 x 310 | 280 x 397 | 291 x 413 | 296 x 420 | 437 x 620 | 583 x 827 | 874 x 1240 | 1748 x 2480 |
| A8 | 147 x 210 | 154 x 219 | 197 x 280 | 205 x 291 | 208 x 296 | 307 x 437 | 409 x 583 | 614 x 874 | 1228 x 1748 |
| US Letter | 612 x 792 | 638 x 825 | 816 x 1056 | 850 x 1100 | 864 x 1118 | 1275 x 1650 | 1700 x 2200 | 2550 x 3300 | 5100 x 6600 |
| Half-Letter | 396 x 612 | 412 x 638 | 528 x 816 | 550 x 850 | 559 x 864 | 825 x 1275 | 1100 x 1700 | 1650 x 2550 | 3300 x 5100 |
| Quarter-Letter | 306 x 396 | 319 x 412 | 408 x 528 | 425 x 550 | 432 x 559 | 638 x 825 | 850 x 1100 | 1275 x 1650 | 2550 x 3300 |
An area of 210 × 279.4 mm fits into both A4 and US Letter sizes: it is the width of A4 and the height of Letter. It's under a millimeter away from 21×28 cm, and that has an aspect ratio of 3:4 (or 4:3, if turned sideways). Therefore, all 4:3 resolutions are only a few pixels bigger than this intersected paper size. The actual aspect ratio of this intersected paper size is about 3.9914:3.
For example, if an image at 1280x960 pixels is rendered at about 116.1 dots per inch, then the 960 pixel dimension fits exactly within 210 mm but the 1280 pixel dimension is 2.7429 pixels and 0.6 mm too large – it overshoots the edge of the page. If it's scaled to fit the other dimension, and rendered at about 109.5 dots per inch, then the 1280 pixel dimension fits the 279.4 mm exactly but the 960 pixel dimension is 2.06156 pixels and 0.48 mm too short.
Created 2026-02-28, last modified 2026-04-16. Index.