| Envelope Type | Metric (Millimeters) Width x Length |
British (Inches) Width x Length |
| A7 | 74 x 105 | |
| A7/A6 | 74 x 148 | |
| B4 | 250 x 353 | |
| B5 | 176 x 250 | |
| B6 | 125 x 176 | |
| B6/C4 | 125 x 229 | |
| 1/2 B4 | 136 x 353 | |
| C3 | 484 x 324 | |
| C4 | 229 x 324 | |
| C5 | 162 x 229 | |
| C6 | 114 x 162 | |
| C65 | 114 x 229 | |
| C7 | 81 x 114 | |
| C7/C6 | 81 x 162 | |
| 1/2 C4 | 125 x 324 | |
| DL | 110 x 220 | |
| Deutsche Industrie Norm Lang | 110 x 220 | |
| E4 | 310 x 220 | |
| E5 | 220 x 115 | |
| E6 | 110 x 156 | |
| E65 | 110 x 220 | |
| 1/2 E4 | 155 x 400 | |
| Hungarian Air Mail | 104 x 160 | |
| Invitation | 220 x 220 | |
| Italian | 110 x 230 | |
| 120 x 180 | ||
| 160 x 230 | ||
| 138 x 230 | ||
| 260 x 360 | ||
| 230 x 341 | ||
| M5 | 155 x 220 | |
| M6 | 110 x 155 | |
| M65 | 110 x 220 | |
| Monarch | 3.875 x 7.5 | |
| Russian Greetings 1 | 187 x 122 | |
| Size 6 3/4 | 3.625 x 6.5 | |
| Size 9 | 3.575 x 8.875 | |
| Size 10 | 4.125 x 9.5 | |
| Size 11 | 4.5 x 10.375 | |
| Size 12 | 4.75 x 11 | |
| Size 14 | 5 x 11.5 |