A-Style
A-Style envelopes are used for sending announcements, small booklets, brochures, and greeting cards. A-sizes have side seam construction, with large, square flaps.
Envelope Size Chart
| Envelope | Size | Enclosure |
| A-2 | 4.375 x 5.75 | 4.25 x 5.5 |
| A-6 | 4.75 x 6.5 | 4.625 x 6.1875 |
| A-7 | 5.25 x 7.25 | 5 x 6.875 |
| A-8 | 5.5 x 8.125 | 5.25 x 7.75 |
| A-Long (Slimline) | 3.875 x 8.875 | 3.75 x 8.625 |
| A-10 | 6 x 9.5 | 5.75 x 9.125 |
Baronial
Baronial envelopes are used primarily for invitations and greetings. Baronial envelopes have diagonal seams, and pointed flaps.
| Envelope | Size | Enclosure |
| Gladstone | 3.5625 x 5.5625 | 3.375 x 5.375 |
| 4 Baronial | 3.625 x 5.125 | 3.5 x 4.875 |
| Astor | 3.625 x 5.625 | 3.5 x 5.375 |
| 5 Baronial | 4.125 x 5.625 | 4 x 5.375 |
| 5 1/2 Baronial | 4.375 x 5.75 | 4.25 x 5.5 |
| 6 Baronial | 4.75 x 6.5 | 4.625 x 6.25 |
| Lee | 5.25 x 7.25 | 5.125 x 7 |
Booklet
Booklet envelopes are used for a wide variety of mailing and shipping functions. They have side seam construction with a wallet flap on the longer side. The term "open side" is sometimes used when referring to booklet envelopes.
| Envelope | Size | Enclosure |
| 6 | 5.75 x 8.875 | 5.5 x 8.375 |
| 6 1/2 | 6 x 9 | 5.75 x 8.5 |
| 6 5/8 | 6 x 9.5 | 5.75 x 9 |
| 6 3/4 | 6.5 x 9.5 | 6.25 x 9 |
| 7 1/2 | 7.5 x 10.5 | 7.25 x 10 |
| 9 | 8.75 x 11.5 | 8.5 x 11 |
| 9 1/2 | 9 x 12 | 8.75 x 11.5 |
| 10 | 9.5 x 12.625 | 9.25 x 12.125 |
Catalog
Catalog envelopes are used for heavy duty mailing and shipping requirements. They have a center seam construction with a wallet flap on the shorter side. The term "open end" is sometimes used when referring to catalog envelopes.
| Envelope | Size | Enclosure |
| 1 | 6 x 9 | 5.75 x 8.5 |
| 1 3/4 | 6.5 x 9.5 | 6.25 x 9 |
| 3 | 7 x 10 | 6.75 x 9.5 |
| 6 | 7.5 x 10.25 | 7.25 x 10 |
| 9 3/4 | 8.75 x 11.25 | 8.5 x 10.75 |
| 10 1/2 | 9 x 12 | 8.75 x 11.5 |
| 12 1/2 | 9.5 x 12.5 | 9.25 x 12 |
| 13 1/2 | 10 x 13 | 9.75 x 12.5 |
| 14 1/2 | 11.5 x 14.5 | 11.25 x 14 |
| 15 | 10 x 15 | 9.75 x 14.5 |
| 15 1/2 | 12 x 15.5 | 11.75 x 15 |
Commercial
Commercial envelopes are used for many business purposes. They have diagonal seams and a standard commercial flap. Commercials are available with or without windows, and can be made with remoistenable seal gum, Peel & Seel, or latex self-sealing closures. The No. 10 envelope is the most popular size and is perfect for inserting a folded letterhead sheet.
| Envelope | Size | Enclosure |
| 6 1/4 | 3.5 x 6 | 3.25 x 5.75 |
| 6 3/4 | 3.625 x 6.5 | 3.5 x 6.25 |
| 7 | 3.75 x 6.75 | 3.5 x 6.5 |
| Monarch (7 3/4) | 3.875 x 7.5 | 3.75 x 7.25 |
| 9 | 3.875 x 8.875 | 3.75 x 8.625 |
| 10 | 4.125 x 9.5 | 4 x 9.25 |
| 11 | 4.5 x 10.325 | 4.25 x 10.125 |
Square
Square envelopes are used for advertising pieces, invitations, and other unique communications. Squares have side seam construction, with large, square flaps.
| Envelope | Size | Enclosure |
| 6 1/2 | 6.5 x 6.5 | 6.25 x 6.25 |
| 7 | 7 x 7 | 6.75 x 6.75 |
| 7 1/2 | 7.5 x 7.5 | 7.25 x 7.25 |
| 8 | 8 x 8 | 7.75 x 7.75 |
| 8 1/2 | 8.5 x 8.5 | 8.25 x 8.25 |
| 9 | 9 x 9 | 8.75 x 8.75 |
| 9 1/2 | 9.5 x 9.5 | 9.25 x 9.25 |
| 10 | 10 x 10 | 9.75 x 9.75 |