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You have to be registered for GST/HST once your taxable sales pass $30,000 in a single calendar quarter or over four quarters in a row. Below that you’re a small supplier and registering is your choice.
When must you register for GST/HST?
The CRA’s test runs on your revenue from taxable sales, counted together with anyone associated with you. Two things trigger registration. One is going over $30,000 across four consecutive calendar quarters. The other is going over $30,000 inside one quarter.
The second case bites harder, and freelancers get caught by it. If one big quarter takes you past $30,000, your registration date is no later than the day of the sale that crossed the line. You start charging GST/HST on that very sale, before you’ve even filled in the form. Then you have 29 days from that date to register.
In the slower case, where you creep over across several quarters, charging starts at the beginning of the month after you stop being a small supplier.
What changes once you’re registered?
Two big things. You charge tax on your taxable sales, and you can claim input tax credits for the tax you paid on business costs. The CRA states both in its general guide for registrants.
Zero-rated sales, such as basic groceries, are still in the system, charged at 0%. Exempt sales are a different category, and the CRA’s supply-type pages explain which is which.
| Item | What the CRA says |
|---|---|
| Small supplier limit | $30,000 in a quarter or over four quarters |
| Time to register after crossing | 29 days from the effective date |
| Charging starts | On the supply that took you over, for a single quarter |
| Voluntary registration | Allowed for small suppliers making taxable sales |
| Minimum time registered voluntarily | One year before you can ask to cancel |
| Filing, revenue up to $1.5M | Annual, with monthly or quarterly as an option |
A worked example with real numbers
Say you run a design business in Ontario and bill $30,000 of work in one quarter. The GST and HST calculator puts 13% on that at $3,900. That $3,900 is not income. It’s the CRA’s money, and you only hold it until you file.
Now say you bought a $500 monitor for the business the same quarter. HST on it was $65. As a registrant you claim that back as an input tax credit. If you’d stayed unregistered, the $65 would just be a cost you absorb.
Notice the catch, though. Your clients now pay 13% more, and some of them can’t claim it back. A private customer sees your price jump by 13% overnight unless you absorb it. That’s the real price of crossing the line, and it’s why some people stay just under it.
Should you register before you have to?
Sometimes. If your clients are other registered businesses, they recover the tax you charge, so it costs them nothing, and you get credits on your own costs. That usually favours registering early, especially when you’re buying equipment.
If you sell mostly to the public, registering early makes you more expensive than a competitor who’s still small. Run both prices. The self-employed tax calculator shows your income tax picture, though it doesn’t handle GST, and its deductions lower income tax but not CPP. Use it beside the sales tax math, not instead of it.
Mistakes that cost money
Watching only the annual total is the big one. The quarterly test catches people who had one huge quarter. Another is forgetting associated businesses, since the $30,000 is counted with theirs.
A third is waiting for the paperwork before charging. The CRA says you charge on the sale that took you over, even if you aren’t registered yet. Miss that and you may owe tax you never collected. Check your running total every quarter. If you need to back tax out of an old invoice, the reverse HST calculator does it.
We didn’t find a fee or penalty figure we could confirm, so we’ve left penalties out. Ask the CRA, or a bookkeeper who files GST/HST returns, if you’ve already missed a date.
Where the numbers come from
The $30,000 threshold, the 29 days, the single-quarter rule and voluntary registration come from the Canada Revenue Agency’s pages on when to register and its general guide for GST/HST registrants, read in September 2026. The HST figure uses Ontario’s 13% rate. This site isn’t connected to the CRA or any government.
Frequently asked questions
What is the GST/HST registration threshold?
$30,000 of taxable sales in a single calendar quarter or over four consecutive quarters, per the CRA.
How long do I have to register?
29 days from the effective date of registration once you pass the limit.
Can I register if I earn less than $30,000?
Yes, a small supplier making taxable sales can register voluntarily. You must then stay registered for at least one year.
What is an input tax credit?
It lets a registrant recover the GST/HST paid on business purchases and expenses.
How often do I file?
With revenue up to $1.5 million the default is annual filing, with monthly or quarterly as options. Larger businesses file more often.
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Information only. This page is general information, not tax, legal or accounting advice. Tax-Services.ca is an independent publisher: we don't prepare or file tax returns or offer tax services, and we have no connection with the CRA, Revenu Québec, any government or any company named on this page. Check the figures that matter with an official source or a qualified professional.