| Unit | Width | Height |
|---|---|---|
| Millimeters (mm) | 210 | 297 |
| Centimeters (cm) | 21 | 29.7 |
| Inches (in) | 8.27 | 11.69 |
| Pixels @72dpi | 595 | 842 |
| Pixels @150dpi | 1240 | 1754 |
| Pixels @300dpi | 2480 | 3508 |
| Feet | 0.689 | 0.974 |
| A4 | Letter | |
|---|---|---|
| Size | 210×297mm | 215.9×279.4mm |
| Inches | 8.27×11.69" | 8.5×11" |
| Ratio | 1:√2 (1.414) | 1:1.294 |
| Used in | Most countries | US, Canada |
A4 is 6mm narrower but 18mm taller than Letter. A4's 1:√2 ratio means it stays proportional when folded or scaled — a key advantage of the ISO 216 standard.
When printing a Letter document on A4, the bottom may be slightly cut off. When printing A4 on Letter, small side margins may appear.
| Name | Width (mm) | Height (mm) | Width (in) | Height (in) |
|---|---|---|---|---|
| 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 |