A4 measures 210 × 297 mm (about 8.27 × 11.69 inches) and is the default office sheet almost everywhere except North America, where Letter (8.5 × 11 in) still wins. Below: millimeters, inches, and 300 DPI pixel sizes.
| Size | Millimeters | Inches | 300 DPI pixels | Typical use |
|---|---|---|---|---|
| A0 | 841 × 1189 | 33.1 × 46.8 | 9933 × 14043 | Posters |
| A1 | 594 × 841 | 23.4 × 33.1 | 7016 × 9933 | Posters |
| A2 | 420 × 594 | 16.5 × 23.4 | 4961 × 7016 | Drawings |
| A3 | 297 × 420 | 11.7 × 16.5 | 3508 × 4961 | Tests, drawings |
| A4 | 210 × 297 | 8.3 × 11.7 | 2480 × 3508 | Everyday documents |
| A5 | 148 × 210 | 5.8 × 8.3 | 1748 × 2480 | Notebooks |
| A6 | 105 × 148 | 4.1 × 5.8 | 1240 × 1748 | Cards |
| Size | Millimeters | Inches | 300 DPI pixels | Typical use |
|---|---|---|---|---|
| B4 | 250 × 353 | 9.8 × 13.9 | 2953 × 4169 | Exams |
| B5 | 176 × 250 | 6.9 × 9.8 | 2079 × 2953 | Notebooks |
| Size | Millimeters | Inches | 300 DPI pixels | Typical use |
|---|---|---|---|---|
| C4 | 229 × 324 | 9 × 12.8 | 2705 × 3827 | A4 envelope |
| C5 | 162 × 229 | 6.4 × 9 | 1913 × 2705 | A5 envelope |
| C6 | 114 × 162 | 4.5 × 6.4 | 1346 × 1913 | Postcard envelope |
| Size | Millimeters | Inches | 300 DPI pixels | Typical use |
|---|---|---|---|---|
| Letter | 216 × 279 | 8.5 × 11 | 2551 × 3295 | US / Canada default |
| Legal | 216 × 356 | 8.5 × 14 | 2551 × 4205 | Legal documents |
| Tabloid | 279 × 432 | 11 × 17 | 3295 × 5102 | Tabloid / ledger |
| Executive | 184 × 267 | 7.25 × 10.5 | 2173 × 3154 | Office memos |
Letter is about 6 mm wider and 18 mm shorter than A4. Drop an A4 PDF onto Letter stock and the margins shift — or the last line gets cropped. If a file is heading across the Pacific, set the generator to the size the printer actually has. More in A4 paper size explained.
Once you know the stock, open lined paper, graph paper, or Cornell notes and pick A4, Letter, Legal, or a custom width and height.
A4 is 210 × 297 mm, which is 21.0 × 29.7 cm, or about 8.27 × 11.69 inches. US Letter is 8.5 × 11 inches (≈ 216 × 279 mm): a bit wider, a bit shorter.
ISO 216 keeps a √2 aspect ratio. Two A4 sheets make A3; fold A4 in half and you get A5. Area doubles (or halves) at each step.