An envelope is an ordinary part of our daily lives especially if you send a lot of written correspondence. People usually just fill out the required info on these envelopes, put a stamp on it, and finally lick the edges to close the whole thing. People don’t usually have to bother with the envelope standard sizes unless they have to. In case you’re given the task of purchasing the supplies for the office then you won’t bother with it anyway.
Everybody knows that there are standard paper sizes used everywhere. But it doesn’t take long to realize that there are also standard international envelope sizes that are to be used with each type of standard sized paper. ISO 269 defines the various standard sizes for envelopes that are to be used for standard paper sizes.
The standard stipulates that if you use an A4 paper then the appropriate envelope size should be a C4, which has dimensions of 229 mm x 324 mm. If your office uses an A3 paper then the matching envelope format will be a C3 (324 mm x 458 mm). If you use an A6 paper, which is actually an A4 paper that is folded twice, then the matching envelope format should be a C6 envelope.
A C6 paper format should be matched with a B6 size envelope (125 mm x 176 mm) while a C5 paper should be matched with a B5 size envelope (176 mm x 250 mm). A C4 size paper should be matched with a B4 format envelope (250 mm x 353 mm). Finally, a B4 size paper should be matched with an E3 size envelope (280 mm x 400 mm).
North American Envelope Standard Sizes
There is a different standard that is in use in North America. However, it should be noted that not all envelope sizes are used for sending mail. Some envelopes are used for gift cards, pay packets, and at times a key. When you look at a chart of the North American standard formats, please note that when they mention an A2 and other similar designations do not necessarily refer to the international standard sizes of the same name.
An A2 envelope format in North America has dimensions of 111.1 mm x 146.1 mm. An A6 envelope on the other hand has dimensions of 120.7 mm x 165.1 mm. An A7 in North America has its dimensions as 133.4 mm x 184.2 mm.
The following are guidelines for sending envelopes that are fit for the US Postal Service. The envelope must be rectangular in shape. It should be 3 1/2″ in height (at least) and 5″ in length. It should have an approximate thickness of around 1/4 of an inch. It should not be more than 6 1/8″ in height or 11 1/2″ in length. Maximum allowed thickness is about a quarter of an inch thick.
These are the envelope standard sizes international and North American standards. Take note of the standard sizes next time you try send mail.