An A2 card measures 4.25 by 5.5 inches folded, and takes an A2 envelope measuring 4.375 by 5.75 inches. It is the default size in North American card making, it cuts two-per-sheet from standard 8.5 by 11 cardstock with nothing wasted, and it mails at the ordinary letter rate.
That is the short answer. The rest of this covers the other standard sizes, which envelope each one needs, and how to get the most cards out of a sheet.
A quick warning about the letter A
The card-making sizes below are not the ISO A-series you know from paper sizes. An ISO A2 sheet is enormous, roughly 16.5 by 23.4 inches. A card-making A2 is a small folded note.
The two systems share letters and nothing else. If you are buying from a European supplier, or reading a tutorial written outside North America, check the actual measurements rather than trusting the letter.
Standard card sizes
All measurements are the finished folded card, in inches.
| Name | Card size | Envelope size | Common use |
|---|---|---|---|
| A1 | 3.5 x 4.875 | 3.625 x 5.125 | Thank you notes, gift enclosures |
| A2 | 4.25 x 5.5 | 4.375 x 5.75 | The everyday standard |
| A6 | 4.5 x 6.25 | 4.75 x 6.5 | Slightly roomier notes |
| A7 | 5 x 7 | 5.25 x 7.25 | Invitations, photo cards |
