International (ISO) Envelope Size Chart
The DIN 678 is a German standard. It is very similar to the ISO specifications.
North American Envelope Size
Requirements for Post Office
International posting regulations state the envelope must be 90 × 140 mm minimum. The postcard length has to be at least equal to the width multiplied by the square root of two. These specifications have been put in place to help make address reading easier.
In the United States, first class mail necessities envelopes of the letter size. The dimensions must be between 5 inches and 11.5 inches wide, 3.5 to 6.125 inches high, and 0.007 to 0.25 inches thick.
Post office preferred envelopes in Australia have 4 boxes with orange colored inks at the right hand part. It is here that post codes are handwritten. Special computer programs are used to read these. During the days of the Soviet Union, envelopes were made with something similar to seven segment LCD.
Since their invention, envelopes have been put to use in many ways. They are commonly employed for sending out letters, invitations and assorted business dealings. Although it is true that emails now widely used for communications, the envelope s still widely employed.
Even with the onset of new technology, it is unlikely that the envelope will be phased out soon. Aside from the above, the envelope is used for invoices, stationery and many more.
These envelope size charts only show the common sizes being used. There are many more, including baronial envelopes and window envelopes. These two are used in the United States for paying bills and making announcements respectively.