What is an Envelope?
An envelope is a common packaging item made of paper or card that is designed to contain a flat object such as a letter or cards for mailing. Although the there are a variety of different size and shapes of envelopes; the international standard ISO 269 defines a set of standard envelope sizes for use with ISO 216 paper sizes.
The most commonly used envelope size is the DL size. Other popular sizes include C3, C4, C5, C6, C7, B4, B5, B6, & DLX.
Australia Post charges standard letter rate for DL, DLX, C6 and large letter rates for C5, C4, B5, & B4.