US Envelope Paper Sizes

6¼ 152 × 89 mm 6¾ 165 × 92 mm 7 172 × 95 mm 7¾ Monarch 191 × 98 mm 8⅝ 219 × 92 mm 9 225 × 98 mm 10 241 × 104 mm 11 264 × 114 mm 12 279 × 121 mm 14 292 × 127 mm 16 305 × 152 mm A1 92 × 130 mm A2 Lady Grey 146 × 111 mm A4 159 × 108 mm A6 Thompson's Standard 165 × 121 mm A7 Besselheim 184 × 133 mm A8 Carr's 206 × 140 mm A9 Diplomat 222 × 146 mm A10 Willow 241 × 152 mm A Long 225 × 98 mm 1 229 × 152 mm 1¾ 241 × 152 mm 3 254 × 178 mm 6 267 × 191 mm 8 286 × 210 mm 9¾ 286 × 222 mm 10½ 305 × 229 mm 12½ 318 × 241 mm 13½ 330 × 254 mm 14½ 368 × 292 mm 15 381 × 254 mm 15½ 394 × 305 mm

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 ratio 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, most commonly 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
They 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)
6¼	152 × 89 mm	6 × 3.5 in
6¾	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
1¾	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
9¾	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