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The $30,000 line is not an annual figure, and that is where most operators get caught. GST/HST for contractors kicks in the moment your taxable sales pass $30,000 in a single calendar quarter or across any four quarters in a row — a rolling window that does not care when your fiscal year ends. A deck builder who has a strong May and June can cross it on a Tuesday afternoon and owe tax on that very sale.
Miss the trigger and the CRA does not shrug. It assesses the GST/HST you should have charged as if you had collected it, and that money comes out of your margin, not your customer’s pocket. On $40,000 of un-taxed Ontario work, that is roughly $5,200 you cannot go back and invoice for.
Why GST/HST for contractors starts earlier than you expect
Two tests run at the same time. The first is the single-quarter test: if taxable revenue in any one calendar quarter exceeds $30,000, you stop being a small supplier immediately, on the sale that pushed you over. The second is the four-quarter test: if the running total of the last four quarters exceeds $30,000, you have until the end of the following month to register and start charging.
Both tests count gross revenue from taxable work, not profit. They also count the revenue of any associated business. If you and your spouse each run a small operation, the CRA adds them together before applying the threshold.
Take a landscaper in Calgary who started taking paid jobs in March. April to June brings in $22,000, then a run of retaining-wall work lands $19,000 in July alone. That July quarter, on its own, has not passed $30,000 yet. But the four-quarter total crossed the line at the end of June, which means he needed to register by the end of July and charge 5% GST on every invoice from that point forward. He finds this out in November, when his accountant asks for the GST number he does not have. Every invoice between August and November now carries a tax bill he never collected.
Registration itself is free and takes minutes through CRA Business Registration Online. It attaches an RT0001 account to your Business Number. The paperwork was never the hard part; the timing was.
What rate GST/HST for contractors carries by province
The rate you charge follows the place of supply — where the work is done — not where your business is registered. A crew based in Ottawa doing a job across the river in Gatineau charges Quebec’s rates on that invoice, and a Fredericton contractor pricing work in Halifax charges Nova Scotia’s 14%, not New Brunswick’s 15%. The table below shows the current picture.
| Province or territory | What you charge on taxable work | Note for contractors |
|---|---|---|
| Ontario | 13% HST | One combined rate, one return |
| Nova Scotia | 14% HST | Dropped from 15% on April 1, 2025 |
| New Brunswick, Newfoundland and Labrador, PEI | 15% HST | One combined rate, one return |
| British Columbia | 5% GST + 7% PST | PST is a separate provincial system with its own rules for real-property contracts |
| Saskatchewan | 5% GST + 6% PST | Separate provincial registration and return |
| Manitoba | 5% GST + 7% RST | Separate provincial registration and return |
| Alberta, Yukon, NWT, Nunavut | 5% GST only | No provincial sales tax |
| Quebec | 5% GST + 9.975% QST | Administered by Revenu Québec, with its own rules |
The split in GST/HST for contractors matters operationally. In the HST provinces, one registration and one return cover everything. In BC, Saskatchewan and Manitoba, the provincial tax is a second regime with its own registration, its own return, and — for contractors working on real property — its own logic about whether you pay the tax on materials or charge it to the customer. Get the federal side right first, then confirm your province’s rules for the work you actually do.
Input tax credits: the part that pays you back
Once registered, GST/HST for contractors runs in both directions: every dollar you pay on business purchases becomes an input tax credit you subtract from what you owe. Lumber, fasteners, fuel, the truck, the compressor, your phone plan, the software you run the business on — the tax paid on all of it comes back through your return. For a materials-heavy trade, ITCs can knock a third or more off the remittance.
That is also why many operators register before they have to. A contractor doing $25,000 of work with $12,000 in materials is paying roughly $1,500 in Ontario HST on those materials with no way to recover it. Registering voluntarily brings that money back, at the cost of charging 13% to customers who, if they are businesses themselves, will simply claim it as their own ITC.
ITCs only survive an audit if the invoices behind them do. The CRA requires the supplier’s name, the date, the amount and — above a modest purchase value — the supplier’s GST/HST registration number. A shoebox of gas receipts with no supplier number on them is a stack of credits the CRA can deny. Keep every material and fuel receipt where you can find it; with SendWork logging each job’s costs against the quote as they happen, the receipts you need at return time are already tied to the work they paid for.
Smaller operators can also use the quick method, which replaces itemized ITCs with a fixed remittance percentage of GST-inclusive sales. It trades precision for simplicity and suits service-heavy businesses under the eligibility ceiling; a materials-heavy contractor usually does better claiming actual ITCs.
Filing, remitting, and where it falls apart
Filing GST/HST for contractors usually means annual filing, which applies up to $1.5 million in taxable sales. The return is due three months after your fiscal year-end. The catch is instalments: if your net tax last year was $3,000 or more, the CRA expects quarterly instalments this year, and it charges interest on any instalment that arrives late or short. Above $1.5 million you file quarterly; above $6 million, monthly. Since 2024 every return has to be filed electronically.
The failure pattern is not complicated. The tax is collected on invoices, lands in the operating account, and gets spent on payroll and materials in a slow month. Come the filing date, the money is gone and the remittance is funded from whatever is in the account that week — or it is not funded at all, and the balance starts accruing interest. The CRA treats collected GST/HST as trust money, which is why it pursues the director personally when a corporation cannot pay it.
The honest read is that late remittance almost never starts as a tax problem. It starts as a receivables problem: invoices that went out late, or went out on time and were not chased, so the tax that should have been collected in June is still sitting in a customer’s inbox in September. Fix the invoicing rhythm and the remittance mostly takes care of itself.
The operator checklist
- Track the rolling four-quarter total, not the calendar year. Check it at the end of every quarter.
- Register through Business Registration Online the moment you cross either test — or earlier, if your ITCs would exceed the admin cost.
- Put your GST/HST number on every invoice, with the tax shown as a separate line at the rate for the province where the work was done.
- Confirm the PST rules for real-property work if you operate in BC, Saskatchewan or Manitoba. They are not the same as the federal rules.
- Keep every supplier invoice with the supplier’s registration number visible. No number, no credit.
- Move the tax out of the operating account as it is collected. A separate account is the simplest discipline that works.
- Diarize the instalment dates if last year’s net tax passed $3,000.
The operator takeaway
GST/HST for contractors is one of the few obligations where the cost of getting it wrong is fully retroactive. The CRA does not forgive the tax you failed to charge; it simply reassigns the bill to you. So this season the moves are clear: know which quarter you are in against the threshold, register the day you cross it, and treat collected tax as money that was never yours. A working invoicing system that closes the loop does more for your remittance than any spreadsheet.
The rates, the tests and the registration steps are set out on the CRA’s GST/HST charge-and-collect pages, which is where any figure in this article should be confirmed before you rely on it for a specific job.
What can wait is the optimization — quick method versus actual ITCs, voluntary early registration, the fiscal year-end choice. Those are accountant conversations. The threshold and the rate on your next invoice are not.
ON MONEY THAT WAS NEVER YOURS
The tax you collect belongs to the CRA. Everything else is your margin — if you can see it.
SendWork sends the invoice the moment the job closes, tracks what is paid and what is still outstanding, and shows the month in one view — so the remittance is funded from money you actually collected, not money you are still chasing.
