EveryCutFileCard and envelope pairs
| Finished card | Cut it flat | Envelope | Envelope in mm |
|---|---|---|---|
| A2: 4.25 × 5.5 in (108 × 140 mm) | 8.5 × 5.5 in, half a letter sheet | A2: 4.375 × 5.75 in | 111 × 146 |
| A7: 5 × 7 in (127 × 178 mm) | 10 × 7 in | A7: 5.25 × 7.25 in | 133 × 184 |
| A6: 105 × 148 mm | 210 × 148 mm, an A5 sheet | C6 | 114 × 162 |
| A5: 148 × 210 mm | 297 × 210 mm, an A4 sheet | C5 | 162 × 229 |
| DL: 99 × 210 mm, a third of A4 | 198 × 210 mm | DL | 110 × 220 |
Work out the flat size
For a side-fold card, the flat width is twice the finished width and the height stays the same. For a top fold, double the height instead. A US letter sheet, 8.5 × 11 in, gives two A2 cards; an A4 sheet gives two A6 cards.
Room inside the envelope
The standard pairs leave 3 to 19 mm of room overall: an A2 card has 3 mm across and 6 mm down, an A6 card in C6 has 9 and 14 mm, and an A5 card in C5 has 14 and 19 mm. A layered card or one with an insert is thicker, so give it more room. To make an envelope for any card, enter the card size plus that room as the pocket size.
A worked example
Our quarter-letter card is 215.9 × 139.7 mm flat, half of a letter sheet. Folded, it is 107.95 × 139.7 mm, the A2 size, and slips into a 111 × 146 mm A2 envelope with 3 mm to spare across and 6 mm down. Our 5 × 7 in card, 127 × 177.8 mm folded, goes in an A7 envelope the same way.
From standards and reference works: W3C: standard page sizes, Wikipedia: Envelope sizes.