US Envelope Paper Sizes

US Envelope Size in cm, inches

There are three main types of envelopes used in the US and they do not correspond to the ISO standard of paper sizes. They are known as Commercial, Announcement and Catalog. Other less known styles of envelope are Baronial, Booklet and Square. To identify the difference between a ISO size and the US size, a hyphen is often inserted between the letter and number. For example, A2 becomes A-2.

Commercial envelopes, also referred to as Office envelopes, are most commonly used in business situations as they are suitable for automated franking and filling. They are long and thin, with an aspect ration of between 1:1.6 and 1:2.2. The most well known commercial envelope is No.10, as it is able to fit Letter size paper folded three times, or Legal size paper folded four times parallel to the shorter side.

Announcement envelopes, also known as A series envelopes, are used for greeting cards, invitations and photographs. Their aspect ratio ranges between 1:1.3 to 1:1.6, which makes them more of a square shape, rather than long and thin like the Commercial envelopes. The most popular announcement envelopes are Lady Grey (A2) and Diplomat (A9).

Catalog envelopes are most commonly used for catalogs, brochures, and are made with a center seam to make them more durable.Their aspect ratio ranges between 1:1.3 and 1:1.5, making them very similar shape to the announcement envelopes.

Size	Millimeters	Inches
6¼ size	152 x 89 mm	6 x 3.5 in
6¾ size	165 x 92 mm	6.5 x 3.6 in
7 size	172 x 95 mm	6.8 x 3.7 in
7¾ Monarch size	191 x 98 mm	7.5 x 3.9 in
8⅝ size	219 x 92 mm	8.6 x 3.6 in
9 size	225 x 98 mm	8.9 x 3.9 in
10 size	241 x 104 mm	9.5 x 4.1 in
11 size	264 x 114 mm	10.4 x 4.5 in
12 size	279 x 121 mm	11 x 4.8 in
14 size	292 x 127 mm	11.5 x 5 in
16 size	305 x 152 mm	12 x 6 in
A1 size	92 x 130 mm	3.6 x 5.1 in
A2 Lady Grey size	146 x 111 mm	5.7 x 4.4 in
A4 size	159 x 108 mm	6.3 x 4.3 in
A6 Thompson's Standard size	165 x 121 mm	6.5 x 4.8 in
A7 Besselheim size	184 x 133 mm	7.2 x 5.2 in
A8 Carr's size	206 x 140 mm	8.1 x 5.5 in
A9 Diplomat size	222 x 146 mm	8.7 x 5.7 in
A10 Willow size	241 x 152 mm	9.5 x 6 in
A Long size	225 x 98 mm	8.9 x 3.9 in
1 size	229 x 152 mm	9 x 6 in
1¾ size	241 x 152 mm	9.5 x 6 in
3 size	254 x 178 mm	10 x 7 in
6 size	267 x 191 mm	10.5 x 7.5 in
8 size	286 x 210 mm	11.3 x 8.3 in
9¾ size	286 x 222 mm	11.3 x 8.7 in
10½ size	305 x 229 mm	12 x 9 in
12½ size	318 x 241 mm	12.5 x 9.5 in
13½ size	330 x 254 mm	13 x 10 in
14½ size	368 x 292 mm	14.5 x 11.5 in
15 size	381 x 254 mm	15 x 10 in
15½ size	394 x 305 mm	15.5 x 12 in