Envelope Sizes

The standard envelope size is defined by the international standard ISO 269, but this standard has now been revoked and replaced with the ISO 216 standard, the paper size standard. Among the international standard sizes, the B series and C series are used more, and the DL format envelopes are the most used in commercial use.

The envelope sizes of US & North American are more diverse than those under the ISO 216 standard. They are mainly divided into three categories: Commercial envelopes, Announcement envelopes and Catalog envelopes. Commercial envelopes are long and thin and suitable for use in offices and commercial occasions. Usually, the ratio of the short side to the long side (aspect ratio) is between 1:1.6 and 1:2.2.

Announcement envelopes are also called A-style or A-series envelopes. They are mainly used for personal use, including photos, greeting cards, etc. The most famous ones are Lady Gray (A2) and Diplomat (A9).

Catalog envelopes are designed for catalogs, brochures and other heavier content. The aspect ratio of catalog envelopes is between 1:1.3 and 1:1.5.

All envelope sizes are shown in the table below.

ISO 216 is an international standard for paper sizes, used across the world except in North America and parts of Latin America. The standard defines the "A", "B" and "C" series of paper sizes, including A4, the most commonly available paper size worldwide.

North American Standard Envelope Sizes

Format	Width × Height (mm)	Width × Height (cm)	Width × Height (in)
6 1/4 (Commercial)	152 × 89 mm	15.2 × 8.9 cm	6 × 3.5 in
6 3/4(Commercial)	165 × 92 mm	16.5 × 9.2 cm	6.5 × 3.6 in
7 (Commercial)	172 × 95 mm	17.2 × 9.5 cm	6.8 × 3.7 in
7 3/4 Monarch (Commercial)	191 × 98 mm	19.1 × 9.8 cm	7.5 × 3.9 in
8 5/8(Commercial)	219 × 92 mm	21.9 × 9.2 cm	8.6 × 3.6 in
9(Commercial)	225 × 98 mm	22.5 × 9.8 cm	8.9 × 3.9 in
10(Commercial)	241 × 104 mm	24.1 × 10.4 cm	9.5 × 4.1 in
11(Commercial)	264 × 114 mm	26.4 × 11.4 cm	10.4 × 4.5 in
12(Commercial)	279 × 121 mm	27.9 × 12.1 cm	11 × 4.8 in
14(Commercial)	292 × 127 mm	29.2 × 12.7 cm	11.5 × 5 in
16(Commercial)	305 × 152 mm	30.5 × 15.2 cm	12 × 6 in
A1 (Announcement)	92 × 130 mm	9.2 × 13 cm	3.6 × 5.1 in
A2 Lady Grey (Announcement)	146 × 111 mm	14.6 × 11.1 cm	5.7 × 4.4 in
A4 (Announcement)	159 × 108 mm	15.9 × 10.8 cm	6.3 × 4.3 in
A6 Thompson's Standard (Announcement)	165 × 121 mm	16.5 × 12.1 cm	6.5 × 4.8 in
A7 Besselheim (Announcement)	184 × 133 mm	18.4 × 13.3 cm	7.2 × 5.2 in
A8 Carr's (Announcement)	206 × 140 mm	20.6 × 14 cm	8.1 × 5.5 in
A9 Diplomat (Announcement)	222 × 146 mm	22.2 × 14.6 cm	8.7 × 5.7 in
A10 Willow (Announcement)	241 × 152 mm	24.1 × 15.2 cm	9.5 × 6 in
A Long (Announcement)	225 × 98 mm	22.5 × 9.8 cm	8.9 × 3.9 in
1 (Catalog)	229 × 152 mm	22.9 × 15.2 cm	9 × 6 in
1 3/4 (Catalog)	241 × 152 mm	24.1 × 15.2 cm	9.5 × 6 in
3 (Catalog)	254 × 178 mm	25.4 × 17.8 cm	10 × 7 in
6 (Catalog)	267 × 191 mm	26.7 × 19.1 cm	10.5 × 7.5 in
8 (Catalog)	286 × 210 mm	28.6 × 21 cm	11.3 × 8.3 in
9 3/4 (Catalog)	286 × 222 mm	28.6 × 22.2 cm	11.3 × 8.7 in
10 1/2 (Catalog)	305 × 229 mm	30.5 × 22.9 cm	12 × 9 in
12 1/2 (Catalog)	318 × 241 mm	31.8 × 24.1 cm	12.5 × 9.5 in
13 1/2 (Catalog)	330 × 254 mm	33 × 25.4 cm	13 × 10 in
14 1/2 (Catalog)	368 × 292 mm	36.8 × 29.2 cm	14.5 × 11.5 in
15 (Catalog)	381 × 254 mm	38.1 × 25.4 cm	15 × 10 in
15 1/2 (Catalog)	394 × 305 mm	39.4 × 30.5 cm	15.5 × 12 in

International Standard Envelope Sizes

Format	Width × Height (mm)	Width × Height (cm)	Width × Height (in)	AR
DL	110 × 220	11 × 22	4.3 x 8.7	2∶1
C7	81 × 114	8.1 × 11.4	3.2 x 4.5	√2∶1
C7/C6	81 × 162	8.1 × 16.2	3.2 × 6.4	2∶1
C6	114 × 162	11.4 × 16.2	4.5 × 6.4	√2∶1
C6/C5	114 × 229	11.4 × 22.9	4.5 × 9	2∶1
C5	162 × 229	16.2 × 22.9	6.4 × 9	√2∶1
C4	229 × 324	22.9 × 32.4	9 × 12.8	√2∶1
C3	324 × 458	32.4 × 45.8	12.8 × 18	√2∶1
B6	125 × 176	12.5 × 17.6	4.9 × 6.9	√2∶1
B5	176 × 250	17.6 × 25	6.9 × 9.8	√2∶1
B4	250 × 353	25 × 35.3	9.8 × 13.9	√2∶1
E4	280 × 400	28 × 40	11 × 15.7	10∶7