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