A standard diagonal seam envelope is the most common style envelope in use today. Its parts are basically the same regardless of its size or name. The corners, flaps, shoulders, throat, seal and seams may vary slightly in size, curvature or shape in different makes and models.

To help you understand the terms used by envelope manufacturers, we have illustrated a basic diagonal seam envelope showing the most common terms applied to its parts. These terms are used regardless of its style - diagonal, side or center seam - open end or open side.

---

 

Different Types of Envelopes

A-Style
A-Style envelopes are used for sending announcements, small booklets, brochures, greeting cards, and more recently for distinctive business stationery. A-sizes have side seam construction, with large, good-looking square flaps.

Baronial
Baronial envelopes are used primarily for invitations and greetings. Baronial envelopes have diagonal seams, and pointed flaps.

Booklet
Booklet envelopes are used for a wide variety of mailing and shipping functions. They have side seam construction with a wallet flap which is located on the longer of the two dimensions. The term "open side" is sometimes used when referring to booklet envelopes.

Catalog
Catalog envelopes are used for heavy duty mailing and shipping requirements. They have a center seam construction with a wallet flap which is on the shorter of the two dimensions. The term "open end" is sometimes used when referring to catalog envelopes.

Commercial
Commercial envelopes (sometimes referred to as Officials) are used for many business and personal correspondence purposes. They normally come with diagonal seams and a standard commercial flap. More often Commercials are offered with a pointed or square flap. Commercials are available with or without windows, and can be manufactured with remoistenable seal gum, Peel & Se el, or latex self-sealing closures. The No. 10 envelope is by far the most popular size in this grouping and is perfect for inserting a normally folded 8-1/2" x 11" letterhead.

Square
Square envelopes are used for advertising pieces, invitations, and other unique communications. Squares have side seam construction, with large, good-looking square

 

Common North American Envelope Sizes Short dimension precedes long dimension; Inch measurements are the finished envelope size; Metric measurements are approximate (calculated at 1 inch = 25.4 mm and rounded off). N.B. Except where noted, the envelope opening/flap is on the long dimension; Sizes identified as nonstandard do not conform to Universal Postal Union requirements for correspondence envelopes.
Name	No.	Inches	MM	Usage and Comments
Commercial	5	3 1/16 x 5 1/2	78 x 140	For correspondence; Nos. 5, 6, and 6 1/4 are nonstandard
	6	3 3/8 x 6	86 x 152
	6 1/4	3 1/2 x 6	89 x 152
	6 1/2	3 9/16 x 6 1/2	90 x 165
	6 3/4	3 5/8 x 6 1/2	92 x 165
Official	7	3 3/4 x 6 3/4	95 x 171	For correspondence; Nos. Data Card, 10, 10 1/2, 11, 12, and 14 are nonstandard
	7 1/2	3 3/4 x 7 5/8	95 x 194
	7 3/4 (Monarch)	3 7/8 x 7 1/2	98 x 190
	Data Card	3 1/2 x 7 5/8	89 x 194
	8 5/8 (Check)	3 5/8 x 8 5/8	92 x 219
	9	3 7/8 x 8 7/8	98 x 225
	10	4 1/8 x 9 1/2	105 x 241
	10 1/2	4 1/2 x 9 1/2	114 x 241
	11	4 1/2 x 10 3/8	114 x 264
	12	4 3/4 x 11	121 x 279
	14	5 x 11 1/2	127 x 292
Window	6 1/4	3 1/2 x 6	89 x 152	For invoices, statements, etc.; die-cut glassine-backed window permits name and address on enclosure to show; Standard window is 4 3/4" wide x 1 1/8" (121 mm x 29 mm); Window position is 7/8" (22 mm) from left edge, 5/8" (16 mm) from bottom (for No. 8 5/8, position is 5/8" [16 mm] from left edge, 13/16" [21 mm] from bottom); Nos. 6 1/4, 10, 11, 12, and 14 are nonstandard
	6 3/4	3 5/8 x 6 1/2	92 x 165
	7	3 3/4 x 6 3/4	95 x 171
	7 3/4	3 7/8 x 7 1/2	98 x 190
	8 5/8	3 5/8 x 8 5/8	92 x 219
	9	3 7/8 x 8 7/8	98 x 225
	10	4 1/8 x 9 1/2	105 x 241
	11	4 1/2 x 10 3/8	114 x 264
	12	4 3/4 x 11	121 x 279
	14	5 x 11 1/2	127 x 292
Remittance	6 1/4	3 1/2 x 6	89 x 152	Extra deep flap (between 3 3/8" [86 mm] and 3 1/2" [89 mm]) can carry printed message; Nos. 6 1/4 and 6 1/2 are nonstandard
	6 1/2	3 1/2 x 6 1/4	89 x 159
	6 3/4	3 5/8 x 6 1/2	92 x 165
	9	3 7/8 x 8 7/8	98 x 225
Banker's Flap & Wallet Flap	10	4 1/8 x 9 1/2	105 x 241	For bulky correspondence; Heavy- weight paper and deep pointed flap (banker's) or squared flap (wallet); All sizes are nonstandard
	11	4 1/2 x 10 3/8	114 x 264
	12	4 3/4 x 11	121 x 279
	14	5 x 11 1/2	127 x 292
	16	6 x 12	152 x 305
Announcement Text	A-2	4 3/8 x 5 3/4	111 x 146	Made with matching text paper; Flap often has deckle edge; Basically square in shape, hence all sizes except Slim are nonstandard
	A-6	4 3/4 x 6 1/2	121 x 165
	A-7	5 1/4 x 7 1/4	133 x 184
	A-8	5 1/2 x 8 1/8	140 x 206
	A-10	6 x 9 1/2	152 x 241
	Slim	3 7/8 x 8 7/8	98 x 225
Baronial	2	3 3/16 x 4 1/4	81 x 108	For formal correspondence, invitations, announcements, greeting cards; Deep pointed flap; Because of broad variety in sizes, availability should be con- firmed with manufacturer/supplier; Basically square in shape, hence all sizes are nonstandard
	4	3 5/8 x 4 5/8	92 x 117
	5	4 1/8 x 5 1/8	105 x 130
	5 1/4	4 1/4 x 5 1/4	108 x 133
	5 1/2	4 3/8 x 5 3/4	111 x 143
	6	5 x 6 1/4	127 x 159
Booklet or Open Side	2 1/2	4 1/2 x 5 7/8	114 x 149	For booklets, folders, direct mail; Basically square in shape, hence all sizes are nonstandard
	3	4 3/4 x 6 1/2	121 x 165
	4 1/4	5 x 7 1/2	127 x 190
	4 1/2	5 1/2 x 7 1/2	140 x 190
	5	5 1/2 x 8 1/2	140 x 216
	6	5 3/4 x 8 7/8	146 x 225
	6 1/2	6 x 9	152 x 229
	6 3/4	6 1/2 x 9 1/2	165 x 241
	7	6 1/4 x 9 5/8	159 x 244
	7 1/4	7 x 10	178 x 254
	7 1/2	7 1/2 x 10 1/2	190 x 267
	8	8 x 11 1/8	203 x 283
	9	8 3/4 x 11 1/2	222 x 292
	9 1/2	9 x 12	229 x 305
	10	9 1/2 x 12 5/8	241 x 321
	13	10 x 13	254 x 330
Catalog or Open End	1	6 x 9	152 x 229	For catalogues, booklets, magazines, reports; Opening/flap on short dimension; All sizes are nonstandard
	1 3/4	6 1/2 x 9 1/2	165 x 241
	2	6 1/2 x 10	165 x 254
	3	7 x 10	178 x 254
	6	7 1/2 x 10 1/2	190 x 267
	7	8 x 11	203 x 279
	8	8 1/4 x 11 1/4	210 x 286
	9 1/2	8 1/2 x 10 1/2	216 x 267
	9 3/4	8 3/4 x 11 1/4	222 x 286
	10 1/2	9 x 12	229 x 305
	12 1/2	9 1/2 x 12 1/2	241 x 317
	13 1/2	10 x 13	254 x 330
	14 1/4	11 1/4 x 14 1/4	286 x 362
	14 1/2	11 1/2 x 14 1/2	292 x 368
Metal Clasp & String and Button	0	2 1/2 x 4 1/4	63 x 108	For mailing bulky papers; Heavy - Height paper; Opening/flap on short dimension; All sizes except Nos. 15, 25, and 35 are nonstandard
	5	3 1/8 x 5 1/2	79 x 140
	10	3 3/8 x 6	86 x 152
	11	4 1/2 x 10 3/8	114 x 264
	14	5 x 11 1/2	127 x 292
	15	4 x 6 3/8	102 x 162
	25	4 5/8 x 6 3/4	117 x 171
	35	5 x 7 1/2	127 x 190
	50	5 1/2 x 8 1/4	140 x 210
	55	6 x 9	152 x 229
	63	6 1/2 x 9 1/2	165 x 241
	68	7 x 10	178 x 254
	75	7 1/2 x 10	190 x 254
	80	8 x 11	203 x 279
	83	8 1/2 x 11 1/2	216 x 292
	87	8 3/4 x 11 1/4	222 x 286
	90	9 x 12	229 x 305
	93	9 1/2 x 12 1/2	241 x 317
	94	9 1/4 x 14 1/2	235 x 368
	95	10 x 12	254 x 305
	97	10 x 13	254 x 330
	98	10 x 15	254 x 381
	105	11 1/2 x 14 1/2	292 x 368
	110	12 x 15 1/2	305 x 394