Guide · Tax for trades
HST registration
for Ontario trades.
Most new trades businesses in Ontario hit the HST question in their first busy season. The rule is simple once you see it laid out, and the part people get wrong is usually not the threshold but how prices are shown to homeowners. Figures here are current as of September 2026.
Published 2026-09-21 · Formory Group
The short answer.
You must register for GST/HST once you stop being a small supplier, which for most businesses means your taxable revenue passes $30,000. The CRA's registration page counts revenue before expenses, from all your businesses and those of your associates, worldwide.
In Ontario the harmonized rate is 13 per cent, according to the CRA's rate table. Below the threshold you can still register voluntarily, and for many trades that is the better choice.
How the $30,000 test works.
There are two ways to cross the line. If your taxable revenue goes over $30,000 in a single calendar quarter, you stop being a small supplier immediately and must charge HST on the very job that pushed you over.
If you pass $30,000 more gradually, over four consecutive calendar quarters, the CRA says you are no longer a small supplier at the end of the month following the quarter in which you crossed. From there, your registration is effective no later than the day of your first sale after that point, and you have 29 days from the effective date to register.
A plumber doing $8,000 a quarter is under the line. The same plumber taking on one $25,000 basement job in a $10,000 quarter is over it for that quarter and should be charging HST on that job. Knowing which case you are in before you quote a large job saves an awkward conversation later.
Track the threshold by calendar quarter.
The test runs on calendar quarters: January to March, April to June, July to September, October to December. A simple habit works: at the end of each quarter, add up the taxable revenue of that quarter and the three before it. If the four-quarter total is getting close to $30,000, decide now whether you will register voluntarily rather than waiting to be pushed over by one job.
Remember the associates rule. If you own another business, or your business is associated with one, their taxable revenue can count toward your $30,000. A second company set up for a side line does not reset the count.
Quotes are where this bites. If you quote a homeowner a price with no HST in March and cross the threshold before the work is done and invoiced in May, the tax position of that job can change between quote and invoice, and that is a question for your accountant, not your customer. When you are close to the line, write quotes as "plus HST if applicable" and explain why.
What changes when you register.
Once registered, you charge and remit HST on your taxable work, and you can claim input tax credits for the HST you pay on business purchases: materials, tools, fuel, the truck. For a trades business with real material costs, those credits add up.
If you are not registered, you do not charge HST at all, and you cannot claim input tax credits. The CRA's general guide for registrants is clear on both points. Charging HST without a registration number is not an option.
When voluntary registration makes sense.
Registering early is usually worth it if much of your work is for GCs, builders, property managers or other businesses. Registered business customers can generally claim back the HST you charge them as input tax credits, so the tax does not make you more expensive to them, while your own credits on materials and equipment reduce your costs.
It is less attractive if you work almost entirely for homeowners and have low material costs. Homeowners cannot recover HST, so 13 per cent on top of your price is a real increase for them. If you register voluntarily, the CRA says you must stay registered for at least one year before you can ask to cancel.
Showing HST on quotes and invoices.
Section 223 of the Excise Tax Act requires a registrant to tell the customer, on the invoice, receipt or written agreement, either the price and the tax separately, or that the amount includes tax. The CRA's guide adds a third route: showing the rate that applies.
For homeowner work signed at the customer's home, Ontario's consumer rules add their own requirement. O. Reg. 17/05, s. 35, says the written agreement must include an itemized price list including taxes and the total amount payable. In practice: show the price, HST and total on separate lines. More on those contracts in home renovation contract rules.
Commercial customers need your registration number to claim their credits. Under the CRA's documentary rules, invoices of $100 or more must show your GST/HST registration number, and invoices of $500 or more need more detail, including the buyer's name and payment terms.
Prices on your website.
The Competition Bureau's drip pricing guidance says an advertised price must be attainable, and extra mandatory fees cannot be added later. The exception is charges imposed by government on the buyer, such as sales tax. So "from $1,200 plus HST" is fine; "from $1,200" with a mandatory disposal fee or truck charge added at invoice time is the kind of thing the Bureau treats as misleading.
If you publish prices, label them one way and stick to it. "All prices plus HST" in small type under the price list is enough. If you are not registered, say nothing about HST; there is none to add. For how a price page fits into the rest of a trade site, see websites for plumbers.
General information, not tax advice. For your own situation, ask the CRA or an accountant.
Questions
Before you ask.
What is the HST threshold for small businesses in Ontario?
$30,000 of taxable revenue, before expenses, over four consecutive calendar quarters or in a single quarter. Past that, registration is mandatory.
Can I charge HST if I am not registered?
No. Unregistered small suppliers do not charge GST/HST and cannot claim input tax credits.
Do contractors have to include HST in advertised prices?
No. Government-imposed charges such as sales tax can be left out of an advertised price, as long as other mandatory fees are included. State clearly that prices are plus HST.
If I register voluntarily, can I cancel later?
Yes, but the CRA says you must stay registered for at least one year before you can ask to cancel.
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