Envelopes
Envelopes come in a number of standard sizes; below are the most common:
Commercial
Standard correspondence style envelopes, U.S. size. Open-side style with gummed flaps. Made in a wide range of colors and textures. No. 10 is often called "legal size."
| No. | SIZE (in inches) |
| 5 | 3 1/16 x 5 1/2 |
| 6 | 3 3/8 x 6 |
| 6 1/4 | 3 1/2 x 6 |
| 6 1/2 | 3 9/16 x 6 1/4 |
| 6 3/4 | 3 5/8 x 6 1/2 |
| 7 | 3 3/4 x 6 3/4 |
| 7 1/2 | 3 3/4 x 7 5/8 |
| 7 3/4 (Monarch) | 3 7/8 x 7 1/2 |
| Data Card | 3 9/16 x 7 5/8 |
| 8 5/8 | 3 5/8 x 8 5/8 |
| 9 | 3 7/8 x 8 7/8 |
| 10 | 4 1/8 x 9 1/2 |
| 10 1/2 | 4 1/2 x 9 1/2 |
| 11 | 4 1/2 x 10 3/8 |
| 12 | 4 3/4 x 11 |
| 14 | 5 x 11 1/2 |
Booklet
For use with booklets, folders, and other types of direct mail. Open-side design permits overall printing.
| No. | SIZE |
| 6 1/2 | 6 x 9 |
| 6 3/4 | 6 1/2 x 9 1/2 |
| 9 | 8 3/4 x 11 1/2 |
| 9 1/2 | 9 x 12 |
| 10 | 9 1/2 x 12 5/8 |
| 13 | 10 x 13 |
Catalog
Open-end style with flap on short side. Often used to mail catalogs and sales literature.
| No. | SIZE |
| 1 | 6 x 9 |
| 1 3/4 | 6 1/2 x 9 1/2 |
| 2 | 6 1/2 x 10 |
| 3 | 7 x 10 |
| 6 | 7 1/2 x 10 1/2 |
| 7 | 8 x 11 |
| 8 | 8 1/4 x 11 1/4 |
| 9 1/2 | 8 1/2 x 10 1/2 |
| 9 3/4 | 8 3/4 x 11 1/4 |
| 10 1/2 | 9 x 12 |
| 12 1/2 | 9 1/2 x 12 1/2 |
| 13 1/2 | 10 x 13 |
| 14 1/4 | 11 1/4 x 14 1/4 |
| 14 1/2 | 11 1/2 x 14 1/2 |
Other types of envelopes include:
| Window |
| Remittance |
| Announcement |
| Baronial |