US Envelope Paper Sizes
PA series (proposed for ISO 216 in 1975, rejected) and F series.
US Envelope Paper Sizes — dimensions in mm and inches
| Format | mm | inches |
|---|
| PA5 | 140 × 210 | 5.51 × 8.27 |
| PA4 | 210 × 280 | 8.27 × 11.02 |
| F4 | 210 × 330 | 8.27 × 12.99 |
| PA3 | 280 × 420 | 11.02 × 16.54 |