GST HST filing Ontario trips up more small business owners than almost any other tax task, because the rules feel simple until they are not. You collect 13%, you send it to the CRA, and in between sit thresholds, deadlines and methods that decide how much work you do and how much you keep. This guide lays out six essential rules for 2026 so you can file with confidence and avoid the penalties that come from getting it wrong.
It is written for Ontario owners and self-employed professionals who want the plain version, not a wall of legislation.
GST HST filing Ontario: the $30,000 threshold
You must register for GST/HST once your worldwide taxable revenue passes $30,000, measured either over four consecutive calendar quarters or within a single quarter. Below that line you are a “small supplier” and registration is optional. This threshold has not changed since 1991 and is not indexed to inflation.
The test is rolling, not tied to your fiscal year, and the timing catches people out. The very sale that pushes you over the line must include HST, and you generally have 29 days from that sale to register. Wait too long and the CRA can backdate your registration, leaving you owing 13% on sales you never charged tax on.
What rate to charge
In Ontario the rate is 13% HST, made up of the 5% federal portion and an 8% provincial portion. But you charge based on where your customer is, not where you are. An Ontario business invoicing a client in Alberta charges 5% GST, and one selling to a customer in British Columbia deals with that province’s rules.
Getting place-of-supply wrong is a common source of errors, so if you sell across provinces, confirm the rate for each customer’s location.
Filing frequency and deadlines
The CRA assigns your filing frequency by your annual taxable sales. Businesses with $1.5 million or less file annually by default, those between $1.5 million and $6 million file quarterly, and those above $6 million file monthly. You can elect to file more often than required, which some owners do to claim refunds faster or to keep the amount owing small.
One rule catches new registrants: you must file every period even if you owe nothing. A nil return is still a required return, and skipping it can trigger penalties.
The Quick Method, and who cannot use it
The Quick Method simplifies filing for smaller businesses. Instead of tracking every input tax credit, you charge customers the full 13% and remit a lower flat percentage of your HST-included sales, keeping the difference as income. For most Ontario service businesses the remittance rate is 8.8%, plus a 1% credit on the first $30,000 of eligible revenue. You elect it by filing Form GST74, and you qualify if your annual taxable supplies are $400,000 or less.
There is a catch that matters here. Accountants, bookkeepers, lawyers and financial consultants are excluded from the Quick Method regardless of revenue, so a bookkeeping firm cannot use it even while recommending it to eligible clients.
GST HST filing Ontario: how to file and avoid penalties
Most businesses file online through NETFILE in the CRA My Business Account, which gives instant confirmation and processes refunds faster than paper. Before you file, total the HST you collected, subtract the input tax credits for HST you paid on business purchases, and remit the difference.
Keep the records that support both figures, since HST is the most audit-triggered tax for small businesses. Filing on time and remitting what you actually owe is the cheapest insurance there is. You can register and file through the CRA My Business Account, and the full rules live on the CRA’s GST/HST for businesses hub.
A common HST mistake to avoid
The costliest error is spending the HST you collect. Because the 13% sits in your account between filings, it can feel like revenue. It is not. Treating it as your own money leaves you scrambling when the return comes due.
A simple fix is to move collected HST into a separate savings account as it comes in, or to file more often so the balance never grows large. Many small businesses elect quarterly filing for exactly this reason.
Handled this way, GST HST filing Ontario becomes a routine transfer rather than a quarterly shock, and you keep the CRA’s money where it belongs until the day it is due.
GST HST filing Ontario: common questions
When does GST HST filing Ontario become mandatory?
Once your taxable revenue passes $30,000 over four quarters or in a single quarter, GST HST filing Ontario is required, and you generally have 29 days from that sale to register.
How often is GST HST filing Ontario due?
The CRA sets your frequency by revenue: annually up to $1.5 million, quarterly to $6 million, monthly above that. You can elect more frequent GST HST filing Ontario if it suits your cash flow.
What is the easiest way to handle GST HST filing Ontario?
File online through the CRA My Business Account, track HST separately as you collect it, and keep your records. Done routinely, GST HST filing Ontario is a quick quarterly task.
The bottom line
GST HST filing Ontario comes down to knowing when to register, what to charge, how often to file, and which method saves you the most. Get those right and the rest is routine. Get them wrong and the CRA’s penalties and interest add up fast.
If HST filing is stealing your evenings, Corporate Empire handles it for Ontario businesses and offers a free 15-minute review to start. Reach us on the Corporate Empire homepage or through our contact page.
