The Goods and Service Tax (GST) is a value added consumption tax instituted by the Federal Government. By law, businesses must charge GST on most goods and services provided. The tax came into effect January 1, 1991.

Most postal services and products are subject to the GST, such as stamps, Advance Purchase Products, all add on options (e.g. Insurance, Trace Mail, COD), optional Postal Box rentals, and postage meter fill ups.

There are certain items sold by Canada Post that are not taxable such as Postal Money Orders, the fee on a Money Order and the exchange on a Money Order. Provincial governments are exempt from paying the GST.

Mail addressed to foreign destinations requiring total shipping charges of $5.00 or more (single item or a cumulative purchase) and products ordered from and shipped directly by Canada Post to a foreign destination, such as Philatelic and Retail products, are not subject to the GST.

The GST is calculated on the total taxable purchase and rounded up or down to the nearest cent.