Oversized Envelope Postage Rates. The postage in the above tables is the required postage for sending letters or documents sent overseas. However, postage paid by prepaid envelopes or stamps will attract GST at the standard rate.
S. rates without a postage scale.
USPS flat rate envelope, a padded envelope is used to secure the parcel with extra safety.
The USPS website has a price calculator- wizard on it's website to help you with how much postage is required… that said— you really want to be careful when estimating the amount needed — because. Oversize or non-standard size envelopes and postcards will cost you more in postage. The postage in the above tables is the required postage for sending letters or documents sent overseas.