The short answer is that most businesses are required to register for the GST / HST, of course, this means they must collect and remit the GST or HST to the Canada Revenue Agency (CRA).
However, some businesses qualify as what the CRA calls a Small Supplier. If your small business qualifies as a Small Supplier, you are not required to register for GST / HST. Now you might be wondering what a the definition of Small Supplier is:
The CRA defines a GST / HST Small Supplier as a sole proprietor, partnership, or corporation whose total taxable revenues before expenses are $30,000 or less in any of the previous four calendar quarters (unless the business is a charity or public service body, where the limit is $50,000).
It is important to note that the Small Supplier GST / HST registration rule does not apply to all types of businesses. For example, taxi and limousine operators must always register for the GST.
Small business owners still have the option to register for GST / HST even if they qualify as a Small Supplier. You may want to register even if your taxable revenues do not exceed $30,000 in the prior four quarters so that you can claim the input tax credits (ITCs) for eligible business purchases that you have paid GST / HST on.