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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)
152.4 × 88.9 mm 6 × 3.5 in
165.1 × 92.1 mm 6.5 × 3.626 in
7 171.5 × 95.3 mm 6.752 × 3.752 in
7¾ Monarch 190.5 × 98.4 mm 7.5 × 3.874 in
8⅝ 219.1 × 92.1 mm 8.626 × 3.626 in
9 225.4 × 98.4 mm 8.874 × 3.874 in
10 241.3 × 104.8 mm 9.5 × 4.126 in
11 263.5 × 114.3 mm 10.374 × 4.5 in
12 279.4 × 120.7 mm 11 × 4.752 in
14 292.1 × 127 mm 11.5 × 5 in
16 304.8 × 152.4 mm 12 × 6 in
A1 92.1 × 130.2 mm 3.626 × 5.126 in
A2 Lady Grey 146.1 × 111.1 mm 5.752 × 4.374 in
A4 158.7 × 108 mm 6.248 × 4.252 in
A6 Thompson's Standard 165.1 × 120.7 mm 6.5 × 4.752 in
A7 Besselheim 184.2 × 133.4 mm 7.252 × 5.252 in
A8 Carr's 206.4 × 139.7 mm 8.126 × 5.5 in
A9 Diplomat 222.3 × 146.1 mm 8.752 × 5.752 in
A10 Willow 241.3 × 152.4 mm 9.5 × 6 in
A Long 225.4 × 98.4 mm 8.874 × 3.874 in
1 228.6 × 152.4 mm 9 × 6 in
241.3 × 152.4 mm 9.5 × 6 in
3 254 × 177.8 mm 10 × 7 in
6 266.7 × 190.5 mm 10.5 × 7.5 in
8 285.8 × 209.6 mm 11.252 × 8.252 in
285.8 × 222.3 mm 11.252 × 8.752 in
10½ 304.8 × 228.6 mm 12 × 9 in
12½ 317.5 × 241.3 mm 12.5 × 9.5 in
13½ 330.2 × 254 mm 13 × 10 in
14½ 368.3 × 292.1 mm 14.5 × 11.5 in
15 381 × 254 mm 15 × 10 in
15½ 393.7 × 304.8 mm 15.5 × 12 in