There are three ranges of sizes, prefixed A, B and C. The most widely used for general printing and letterhead stationery is the A series. The international letterhead size is an A4.
Standard International Paper Sizes
| size | inches | millimeters |
|---|
| A0 |
33-1/8 x 46-13/16 |
841 x 1188 |
| A1 |
23-3/8 x 33-1/8 |
549 x 841 |
| A2 |
16-1/2 x 23-3/8 |
420 x 594 |
| A3 |
11-3/4 x 16-1/2 |
297 x 420 |
| A4 |
8-1/4 x 11-3/4 |
210 x 297 |
| A5 |
5-7/8 x 8-1/4 |
148 x 210 |
| A6 |
4-1/8 x 5-7/8 |
105 x 148 |
| A7 |
2-15/16 x 4-1/8 |
74 x 105 |
| A8 |
2-1/16 x 2-15/16 |
52 x 74 |
Standard International Envelope Sizes
| size | inches | millimeters |
|---|
| C4 |
12-3/4 x 9 |
324 x 229 |
| C5 |
6-3/8 x 9 |
162 x 229 |
| C6 |
4-1/2 x 6-3/8 |
114 x 162 |
| C7/6 |
3-1/2 x 6-1/2 |
89 x 165 |
| DL |
4-1/4 x 8-5/8 |
110 x 220 |
