GST/HST is a tax you collect on behalf of the government — you add it to your prices, hold it, and remit it. The question for most small businesses is not whether the tax exists, but at what point they are required to start charging it. That line is the small-supplier threshold, and it sits at $30,000.
How the $30,000 threshold works
You are a "small supplier" — and exempt from having to register — as long as your worldwide taxable revenues stay under $30,000. The test looks at a rolling window, and there are two ways to cross it:
- Over four consecutive calendar quarters. If your total taxable revenue exceeds $30,000 across the last four quarters, you stop being a small supplier and must register (with a short grace period before you have to start charging).
- In a single calendar quarter. If you blow past $30,000 in one quarter alone, you cease to be a small supplier immediately, and you must charge GST/HST on the sale that put you over.
The threshold is based on revenue, not profit, and it counts your taxable sales before expenses. It is easy to cross without realising, especially in a strong quarter.
If you should have registered and didn't, the CRA can still assess the GST/HST you were supposed to collect — meaning it comes out of your own pocket, on sales where you never charged the customer. Monitoring the threshold matters.
Why you might register before you have to
Registration is not only an obligation — it can be an advantage. Once registered, you can claim input tax credits (ITCs), which recover the GST/HST you pay on business purchases. For a new business that is investing in equipment, inventory, or professional services, those credits can add up quickly.
Voluntary registration tends to make sense when:
- Your customers are mostly other businesses, who claim back the tax you charge them anyway, so charging it costs them nothing.
- You have significant start-up costs and want to recover the tax on them.
- You expect to cross $30,000 soon and would rather set up cleanly from the start.
It tends to make less sense when you sell mainly to individual consumers, where adding tax makes you visibly more expensive than an unregistered competitor.
After you register
Once you have a GST/HST number you charge the correct rate for your province (in Ontario, HST is 13%), file returns on a schedule the CRA assigns based on your revenue — monthly, quarterly, or annually — and remit the difference between the tax you collected and the ITCs you claimed. The most common money left on the table is unclaimed ITCs, simply because purchase records were not kept cleanly through the year.
This article is general information. The small-supplier rules have specific exceptions (for example, taxi and ride-share operators must register regardless of revenue), rates vary by province, and thresholds can change. Confirm your situation on canada.ca or with your accountant.