When do I have to register for HST in Ontario?
The CRA uses one test for most businesses: are you still a small supplier? You stop being one when your taxable sales pass $30,000 in either of two ways, and the timing is different for each. The rules are on the CRA's page When to register for and start charging the GST/HST.
- You pass $30,000 inside one calendar quarter. You stop being a small supplier on the sale that takes you over. HST applies to that sale too.
- You pass $30,000 over four calendar quarters in a row, without doing it in any one quarter. You stop being a small supplier at the end of the month after the quarter in which you crossed the line. You charge HST from your first sale after that day.
Calendar quarters always start on 1 January, 1 April, 1 July and 1 October, whatever your company's year-end is. Once you are past the line, you have 29 days from your effective date of registration to get the HST number.
What counts toward the $30,000?
Revenue before expenses from taxable sales, including zero-rated ones, made inside and outside Canada. Three details catch owners out.
First, the count uses sales before expenses. A contractor who bills $34,000 in a year and spends $20,000 on materials is over the line.
Second, associated businesses count together. A sole proprietor adds the taxable sales of every business they run and those of their associates. A corporation adds the sales of associated corporations. Two small companies owned by the same person can each look small and still be over $30,000 combined.
Third, some income is left out: financial services, sales of capital property and goodwill on the sale of a business. Exempt sales also sit outside the count. Most residential rent is exempt, and so are most services a physician bills to OHIP. A landlord with three long-term residential units, or a doctor whose income is all OHIP billings, can earn far more than $30,000 and still have nothing to register for. You generally cannot register at all if everything you sell is exempt.
A worked example: a new consulting business
The CRA gives this one. A consultant starts on 1 January and bills $2,000 in the first quarter, $10,000 in the second and $38,000 in the third. The third quarter alone is over $30,000, so the consultant stops being a small supplier on the invoice that crossed the line, charges HST on that invoice and every one after it, and registers within 29 days.
Change the numbers to $25,000 in October to December and $25,000 in January to March. No single quarter is over $30,000, but the two together are $50,000. The business stops being a small supplier on 30 April, the end of the month after the quarter it crossed the line, and charges HST from its next sale.
If you track sales by month in your books, the quarter test takes five minutes. If you only look once a year at tax time, it is easy to be six months late before anyone notices.
What if I crossed the line months ago and never registered?
You owe HST on your taxable sales from the day you stopped being a small supplier, even on invoices that never showed it. Collecting it from customers after the fact is often not possible, so the 13% usually comes out of your margin. The sooner you register and file the returns for the missed periods, the smaller that gets. We do this catch-up regularly: register with the right effective date, rebuild the periods from your bank and sales records, claim the input tax credits you are entitled to for the same periods, and file. If it would help to talk it through first, our HST returns page sets out how we work.
Does anyone have to register before $30,000?
Yes. Self-employed taxi operators and commercial ride-share drivers must register even as small suppliers, from their first taxable fare. The CRA explains this on its page for taxi operators and commercial ride-sharing drivers. Charities and public institutions use a different test with a $50,000 threshold and a $250,000 gross revenue check.
Should I register voluntarily while I am under $30,000?
Sometimes it is worth it. Registering lets you claim input tax credits, which means the HST you pay on equipment, software, rent and supplies comes back to you. That matters most when your customers are other HST-registered businesses, because they claim back the HST you charge them and your price does not really go up for them.
It matters less when you sell to the public. A homeowner or a shopper cannot claim the 13% back, so either your price rises or your margin falls.
The CRA's voluntary registration page lists what you sign up for: charge and remit HST, file returns on schedule, and stay registered for at least one year before you can cancel, unless you stop your commercial activity. Your effective date can usually go back up to 30 days before you apply, but a corporation's cannot go back before the date it was incorporated.
I just incorporated. Do I need a new HST number?
The corporation is a new person for tax purposes. If you ran as a sole proprietor with an HST number and you move the business into a company, the company needs its own GST/HST account under its own business number once it has to register or chooses to. Plan the switch date with your accountant so invoices, the bank account and the HST account all change on the same day. Our incorporation service includes setting up the program accounts in the right order.
How do I check where I stand today?
- Pull your taxable sales by calendar quarter for the last four quarters, from your invoices or your bank deposits.
- Take out exempt income, such as residential rent or OHIP billings, and any capital property you sold.
- Add the taxable sales of any business associated with you.
- If one quarter is over $30,000, or the four together are, find the date you crossed the line. That date sets your effective date and the 29-day clock.
Our Ontario HST calculator works out the tax on a price, and the tax dates page shows when HST returns are due once you have a number.
How Wealthy Wave Accounting helps
We work with owners across Ontario from our office at 181 Queen St E in Brampton and by Teams. For businesses close to the line we check the quarter test from your books, register the account with the right effective date, and file your HST returns from reconciled records so the input tax credits are supported if the CRA asks. If you have already crossed the line, we fix the past periods before they grow.
General information only, based on CRA guidance as of November 2026. Your own facts decide the answer, so talk to us before you register or file.