HST Business Threshold Checker
When a Mississauga business has to start charging HST
The $30,000 small-supplier threshold is the most misunderstood number in Canadian self-employment. It is not an annual allowance that resets each January, and crossing it does not give you until tax time to deal with it.
Thirty thousand dollars in taxable revenue
You remain a small supplier — and may choose not to register — while your taxable revenue stays at or below $30,000. The test runs over four consecutive calendar quarters on a rolling basis, so it can be crossed in the middle of a year rather than at year end.
The threshold counts gross revenue, not profit. Expenses, subcontractor payments and materials do not come off before the test is applied, which is why so many trades and consultants cross it earlier than they expect.
You get 29 days, not a filing season
Once you exceed the threshold your effective registration date is immediate, and you have a 29-day window to register with CRA. HST is owed on the sale that crossed the line, whether or not you charged it to the client.
That is the expensive part of missing it. If you invoiced without HST and later have to remit it, the 13% comes out of money you have already been paid — along with interest and penalties that are not advertised upfront.
Registering early can pay for itself
Registration is not purely a cost. Once registered you can claim input tax credits on the HST you pay on business purchases — equipment, software, a work vehicle, professional fees — which a small supplier simply absorbs.
For a business with real expenses, or one selling mainly to other registered businesses that recover the HST anyway, voluntary early registration often comes out ahead. The full HST guide works through the cash-flow method that makes the first year manageable.
This checks the threshold, not your whole tax position
The tool tells you where you stand against the $30,000 line. It does not calculate what you owe, choose your reporting period, or assess whether the Quick Method would reduce your remittance.
It also does not address the separate municipal question of whether Mississauga requires a licence for what you do — see the business licensing calculator for that, and the home business framework if you operate from home.
Crossing $30,000 starts a 29-day clock, and the HST is owed on the sale that crossed it — so track the rolling four-quarter figure rather than waiting for a year-end total.
Sources & assumptions
- Canada Revenue Agency — GST/HST small supplier threshold and registration requirements
- Ontario HST rate: 13% (5% federal, 8% provincial)
- General guidance for sole proprietors and small corporations. Charities, public institutions, and taxi or ride-share drivers fall under different rules — confirm your position with an accountant.
Figures reviewed August 2026. Rates change — check the linked source before relying on a number for a filing or a closing.