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US Envelope Paper Sizes

Further Information

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.

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