You must register for GST/HST once your taxable revenue passes $30,000, you charge the rate of the province where the work is done, and you claim back the tax you pay on business costs as input tax credits. That is the whole system in one sentence. The detail is where tradespeople lose money: the threshold is gross revenue not profit, the timing rules have a hard 29-day deadline, the rate map runs from 5 percent to nearly 15 percent across the country, and the Quick Method can either save you thousands or cost you, depending on how materials-heavy your work is. This is the complete, definitive guide to getting GST/HST right.
The $30,000 small-supplier threshold
GST/HST is the federal Goods and Services Tax, harmonised in some provinces with the provincial sales tax into a single Harmonized Sales Tax. While your worldwide taxable revenue stays at or below $30,000, you are a "small supplier" and you do not have to register or charge it. Cross $30,000 and registration becomes mandatory.
Three things trip people up about the threshold:
- It is gross revenue, not profit. A tradesperson who bills $32,000 but spends $12,000 on materials has still crossed the line. The test is revenue before any expenses.
- It is cumulative across everything you do. The $30,000 applies to all your business activities and all your trade names combined. You cannot run "Mike's Roofing" and "Mike's Eavestroughing" as two names to get two thresholds. The Canada Revenue Agency (CRA) adds them together.
- For most established trades it arrives fast. Thirty thousand dollars is one or two decent jobs. Construction labour and materials are taxable supplies, so registration is effectively automatic for anyone working full time.
The timing rules: the 29-day deadline
How and when you must register depends on how you cross the line, and there are two distinct rules:
- You exceed $30,000 in a single calendar quarter. You stop being a small supplier immediately. You must register straight away and charge GST/HST on the very supply that pushed you over the line, and on everything after it.
- You exceed $30,000 over four consecutive calendar quarters (but no single quarter on its own takes you over). You stop being a small supplier at the end of the month following that quarter, and you must register within 29 days of the day you became liable.
If you are unsure which case applies, register as soon as you can see $30,000 coming. Charging tax a little early is far easier to fix than charging it late, because if you register late you are still liable to the CRA for the tax you should have collected, whether or not you actually charged it to the client.
Registering, step by step
You register a GST/HST account against your CRA Business Number (BN). If you do not have a BN yet, one is created as part of the same process (see The CRA Business Number and Program Accounts). The GST/HST account carries the program code RT.
- Register online through CRA My Business Account or Business Registration Online at canada.ca, or by mail. Note that the CRA stopped taking business registrations by phone on November 3, 2025.
- Have your SIN, legal name, business name and a description of your activity ready.
- You pick or are assigned a reporting period: annual, quarterly or monthly. Smaller businesses often default to annual (less paperwork, one larger payment), while quarterly spreads the remittance and is easier on cash flow for many trades. Whichever you pick, you must file every period, even a nil return.
In Quebec, GST is administered by Revenu Quebec rather than the CRA, so a Quebec contractor registers with Revenu Quebec for both the federal GST and the provincial QST together (see the Quebec section below).
Charging the right rate by province
The rate you charge depends on where the work is supplied, not where your shop is. A British Columbia contractor doing a job in Alberta charges 5 percent, not 12 percent. The complete 2026 rate map for all thirteen jurisdictions:
- Alberta, Northwest Territories, Nunavut, Yukon: 5 percent (GST only, no provincial sales tax).
- Saskatchewan: 11 percent (5 percent GST plus 6 percent PST).
- British Columbia: 12 percent (5 percent GST plus 7 percent PST).
- Manitoba: 12 percent (5 percent GST plus 7 percent RST).
- Ontario: 13 percent (HST).
- Nova Scotia: 14 percent (HST, cut from 15 percent on April 1, 2025).
- Quebec: 14.975 percent (5 percent GST plus 9.975 percent QST).
- New Brunswick, Newfoundland and Labrador, Prince Edward Island: 15 percent (HST).
In the participating HST provinces (Ontario, Nova Scotia, New Brunswick, Newfoundland and Labrador, Prince Edward Island) the federal and provincial sales tax are blended into one rate that you collect and remit together with the CRA. In British Columbia, Saskatchewan and Manitoba the provincial PST or RST is a separate tax with its own rules about what is taxable (in British Columbia, for instance, PST often applies to materials while labour is frequently exempt), so you register for GST with the CRA and for the provincial tax separately with the province.
Input tax credits: the point of registering
The reason registration is not just a cost is the input tax credit (ITC). Once registered, you claim back the GST/HST you paid on business purchases. On the standard method, every return has two sides: the tax you charged clients, and the tax you paid on materials, tools, equipment, subcontractor invoices, fuel and the business share of mixed-use costs. You subtract your ITCs from the tax you collected and remit the difference. If you paid more than you collected, for example in a quarter you bought a van, the CRA refunds the excess.
The documentary rules matter, and the bar rises with the size of the purchase:
- Under $100: the supplier name, the date, and the total paid.
- $100 to under $500: the above, plus the supplier's GST/HST registration number, and either the tax amount or a statement that the total includes it.
- $500 or more: the above, plus your name, a description of what was supplied, and the terms.
A till slip with no GST/HST number on a $300 purchase does not support the credit. Keep every supporting document for six years; the CRA can deny a credit you cannot back up. The detail is in Input Tax Credits, Explained.
The Quick Method: when it pays and when it does not
The Quick Method is a simplified alternative. Instead of tracking every input tax credit, you remit a flat percentage of your tax-included sales and keep the difference, which is meant to approximate the credits an average business in your category would have claimed. Any business with worldwide annual taxable revenue of $400,000 or less can elect it by filing Form GST74. Accountants, bookkeepers, lawyers and financial institutions are barred, but construction contractors and the trades qualify.
Under the Quick Method you still charge clients the normal rate. You generally cannot claim ITCs on day-to-day operating costs (the lower remittance rate accounts for them), but you can still claim ITCs separately on capital purchases such as a vehicle or major equipment. There is also a 1 percent credit on the first $30,000 of eligible supplies each fiscal year, worth up to $300.
The remittance rate for a trade or service business doing all its work in its home province, for 2026, runs roughly:
- Ontario (13 percent HST): about 8.8 percent.
- Nova Scotia (14 percent HST): about 9.4 percent.
- New Brunswick, Newfoundland and Labrador, Prince Edward Island (15 percent HST): about 10.0 to 10.4 percent.
- Alberta, British Columbia, Saskatchewan, Manitoba and the territories (work supplied at 5 percent GST): about 3.6 percent.
The Quick Method wins for high-labour, low-materials work. An Ontario renovator who bills $200,000 plus 13 percent HST collects $26,000 of HST on $226,000 of tax-included sales. Remitting at the illustrative 8.8 percent rate gives about $19,888, and the gap of roughly $6,000, less the operating-cost credits given up, plus the $300 one-percent credit, is the benefit. A builder buying large volumes of HST-bearing materials would forfeit big input tax credits and is usually better off on the standard method. Run both before electing. One honesty note: these consolidated remittance percentages should be confirmed against the CRA's current guide RC4058 before you rely on a number, because that table is periodically updated. Do not copy a rate off a blog, including this one, without checking RC4058. There is a fuller treatment in The GST/HST Quick Method, Explained.
Filing, remitting and the trust trap
You file a GST/HST return for every reporting period and remit the net tax. The single most important thing to understand is that the GST/HST you collect is not your money. It is the CRA's, held in trust. It is not business income, it does not belong on your T2125, and the CRA pursues unremitted GST/HST harder than ordinary tax debt: trust amounts can survive even bankruptcy. The discipline that saves trades is to bank the tax separately the day it lands and never treat it as cash flow.
Quebec: GST plus QST, run separately
Quebec stands alone. The CRA administers the federal GST; Revenu Quebec administers the 9.975 percent Quebec Sales Tax (QST). If you do work in Quebec you need two registrations, and you collect both taxes for a combined 14.975 percent. A business based outside Quebec registers for QST through Revenu Quebec using Form LM-1-V. Charging only GST on Quebec work and forgetting the QST is a common and expensive error.
A note on new housing
New residential construction can carry GST/HST rebates such as the GST/HST New Housing Rebate, but those are claimed by the owner or buyer, not by you. As the contractor you charge the full applicable HST and the client applies for any rebate. Misapplied tax treatment on new builds is a frequent audit trigger, so get the rebate rules straight before you quote a new build.
Common mistakes
- Testing on profit instead of revenue. The $30,000 threshold is gross revenue. A materials-heavy job counts in full, and crossing the line is mandatory registration.
- Splitting trade names to stay small. The threshold is across all your activities combined. Two names do not buy two thresholds.
- Charging your home rate everywhere. The rate follows the place of supply. Charge the rate of the province where the work is done.
- Spending the GST/HST you collected. It is trust money owed to the CRA. Bank it separately; it can outlast bankruptcy.
- Electing the Quick Method with heavy materials. Big material purchases mean big input tax credits you forfeit. Compare both methods on real numbers first.
- Forgetting Quebec's QST. Work in Quebec needs a separate Revenu Quebec registration on top of GST.
Know someone who needs this?
Keep reading
Was this guide useful?
Didn't find what you were looking for?
Spotted something wrong or out of date? Email us at hello@kilnguides.co.uk.
In crisis? 988 Suicide Crisis Helpline (call or text 988) ·