GST/HST for Ontario Businesses: Registration, Filing, and Input Tax Credits

The Harmonized Sales Tax (HST) touches almost every business in Ontario, yet it’s one of the areas where well-run businesses most often make expensive mistakes. Some register too late and end up owing HST they never collected. Others register on time but leave thousands of dollars of input tax credits unclaimed. Many simply don’t understand why their HST return shows a balance owing when they “didn’t make any money.”

This guide explains how HST works for Ontario businesses, when you need to register, how to file, how to recover the HST you pay, and which mistakes to avoid. It’s written for owners, not tax specialists.

Key takeaways

• HST in Ontario is 13%: 5% federal GST plus 8% provincial.
• You generally must register once your taxable revenue exceeds $30,000 in a single calendar quarter or over the last four consecutive calendar quarters (the small supplier threshold).
• HST you collect isn’t your money. It’s held in trust for the government, and directors can be personally liable for unremitted amounts.
• Input tax credits (ITCs) let you recover HST paid on business purchases, but only with proper documentation and within time limits.
• The Quick Method can simplify filing and sometimes reduce net HST for smaller service businesses.

How HST works

HST is a value-added tax. At each stage of the supply chain, a registered business charges HST on its sales and recovers the HST it paid on its own business inputs. The net difference is remitted to the CRA (or refunded if the business paid more than it collected). The tax ultimately falls on the final consumer.

In Ontario, the rate is 13%. Other provinces have different rates: some participate in HST at different rates, while others charge only the 5% GST, sometimes with a separate provincial sales tax administered by the province.

A simple example

A Toronto marketing agency invoices a client $10,000 plus $1,300 HST. During the same period, it buys a laptop for $2,000 plus $260 HST and pays $3,000 plus $390 HST in rent.

• HST collected: $1,300
• Input tax credits: $260 + $390 = $650
• Net HST owing: $1,300 − 650 = * *650**

The agency remits $650 to the CRA. Its customers paid the $1,300, and the agency recovered the $650 it paid to suppliers.

Types of supplies: taxable, zero-rated, and exempt

Not everything is taxed the same way. Understanding the categories matters because they affect both what you charge and whether you can claim ITCs.

• Taxable supplies are subject to HST at 13% in Ontario. Most goods and services fall here.
• Zero-rated supplies are taxable at 0%. You don’t charge HST, but you can claim ITCs on related purchases. Examples include basic groceries, most prescription drugs, many medical devices, and most exports of goods and services.
• Exempt supplies aren’t subject to HST, and you cannot claim ITCs on related purchases. Examples include most residential rent, many health care services, most financial services, child care, and certain educational services.

A business that makes only exempt supplies generally can’t register for HST and can’t recover the HST it pays. A business with a mix of taxable and exempt supplies must apportion its ITCs.

When you have to register

The small supplier threshold

You’re a small supplier if your worldwide revenue from taxable supplies (including zero-rated supplies), together with that of associated persons, is $30,000 or less in a single calendar quarter and over the last four consecutive calendar quarters. Small suppliers aren’t required to register.

You stop being a small supplier:

• If you exceed $30,000 in a single calendar quarter: you’re considered a registrant from the supply that pushed you over, and you must charge HST on that supply. You must register within 29 days.
• If you exceed $30,000 over four consecutive calendar quarters (but not in any single quarter): you stop being a small supplier at the end of the month following the quarter in which you crossed the threshold, and you must register within 29 days of the first supply after that.

Mandatory registration regardless of revenue

Some businesses must register from day one, regardless of revenue. These include taxi and commercial ride-sharing drivers, and certain non-resident businesses that come under specific rules. If you drive for a ride-share platform, register before you start.

Voluntary registration

Even if you’re a small supplier, you can register voluntarily. Reasons to consider it:

• You can claim ITCs on start-up costs and ongoing purchases.
• Your customers are businesses, who can recover the HST you charge them, so charging HST doesn’t make you less competitive.
• You expect to cross the threshold soon and want to avoid scrambling.
• Some clients prefer dealing with registered suppliers.

Reasons to wait:

• Your customers are mostly consumers, who can’t recover HST, so adding 13% to your price may matter.
• Your expenses are low, so the ITCs wouldn’t amount to much.
• You want to avoid filing obligations while you’re very small.

Once registered, you generally need to stay registered for at least a year before you can cancel.

Charging HST correctly

Once registered, you must:

• Charge HST at the correct rate based on the place of supply. If you’re an Ontario business selling to a customer in another province, the rate is usually based on where the customer is, not where you are. The place-of-supply rules differ for goods, services, and intangible property and can be technical.
• Show your GST/HST registration number on invoices where required, so your business customers can claim ITCs.
• Collect HST on taxable supplies even if you forget to show it on the invoice. If you charge a customer $1,000 and forget the HST, you may be considered to have collected HST out of the $1,000.

Selling outside Canada

Most exports of goods and many services supplied to non-residents are zero-rated. You don’t charge HST, but you can still claim ITCs. The conditions for zero-rating services to non-residents are specific, so confirm before assuming.

Filing frequency

When you register, the CRA assigns a filing frequency based on your annual taxable revenue:

Due dates

• Monthly and quarterly filers: returns and payments are due one month after the end of the reporting period.
• Annual filers: returns and payments are generally due three months after the end of the fiscal year.
• Annual filers who are individuals with business income and a December 31 fiscal year-end: the return is due June 15, but payment is due April 30.

Annual filers and instalments

If you file annually and your net tax for the previous year was $3,000 or more, you generally have to pay quarterly instalments during the year. Instalments are due one month after the end of each fiscal quarter.

Should you choose more frequent filing?

Filing quarterly or monthly, even if you’re eligible to file annually, has advantages:

• Smaller, more predictable payments instead of one large bill.
• Faster refunds if you’re usually in a refund position, such as exporters or businesses with large start-up costs.
• Better discipline, because the bookkeeping has to be current.

The trade-off is more filings. For many small businesses, quarterly is a good balance.

Electronic filing

Nearly all GST/HST registrants must now file returns electronically, with limited exceptions such as charities and certain financial institutions. Most businesses file through CRA My Business Account, GST/HST NETFILE, or their accounting software, or have their accountant file on their behalf.

Input tax credits: getting your HST back

ITCs are where the money is. Every dollar of HST you’re entitled to recover and don’t claim is a direct cost to your business.

What you can claim

You can generally claim ITCs for HST paid on purchases used in your commercial activities (making taxable or zero-rated supplies). That includes inventory, equipment, rent, professional fees, software, marketing, phone, internet, vehicle costs, and most other business expenses.

Restrictions

• Meals and entertainment: ITCs are generally limited to 50% of the HST paid, matching the income tax rule.
• Personal use: you can only claim the business-use portion.
• Passenger vehicles: ITCs are limited based on the vehicle’s cost and business-use percentage.
• Exempt activities: no ITCs for purchases related to exempt supplies.
• Club memberships and certain recreational facilities: generally not claimable.

Documentation requirements

To support an ITC, you need documentation containing specific information, depending on the amount:

Without proper documentation, ITCs can be denied on review, even if you genuinely paid the tax.

Time limits

Most small businesses have four years from the due date of the return for the reporting period in which the ITC could first have been claimed. Large businesses and listed financial institutions have shorter windows. If you’re behind on bookkeeping, old ITCs may be at risk.

The Quick Method

The Quick Method of accounting is an optional, simplified way for eligible smaller businesses to calculate net HST.

How it works

Instead of tracking HST paid on every operating expense, you:

• Charge HST at the normal rate (13% in Ontario).
• Remit a fixed percentage of your HST-included sales. In Ontario, the remittance rates are 8.8% for businesses that mainly provide services and 4.4% for businesses that mainly purchase goods for resale.
• Receive a 1% credit on the first $30,000 of eligible HST-included sales each year.
• Claim ITCs separately for capital purchases such as equipment and vehicles.

Who’s eligible

Generally, businesses with annual worldwide taxable sales (including those of associated persons, and including HST) of $400,000 or less in at least one of the last four fiscal quarters. Certain businesses, such as accountants, lawyers, bookkeepers, financial consultants, and tax preparers, can’t use it.

Is it worth it?

The Quick Method tends to benefit service businesses with relatively low taxable expenses, because the remittance rate is set assuming an average level of ITCs. If your operating expenses with HST are low, you may keep part of the HST you collect. If your HST-bearing expenses are high, the regular method is usually better.

Running the numbers both ways is the only reliable way to know. You must elect into the Quick Method using Form GST74, and generally stay in it for at least one year.

Common HST mistakes

Registering late

If you crossed the $30,000 threshold months ago and didn’t register, you may owe HST on sales you made after you were required to register, even though you never charged it to customers. That HST often comes out of your own pocket.

Treating HST as revenue

HST collected is held in trust. Spending it on operations and then scrambling to pay the return is a cash-flow trap. Consider moving HST collected into a separate savings account each month.

Recording expenses including HST

If you record a $565 expense when $65 of it is recoverable HST, you overstate expenses and miss the ITC. Set up HST codes correctly in your accounting software.

Claiming ITCs without documentation

Bank and credit card statements alone are usually not enough to support ITCs on larger purchases.

Wrong place-of-supply rate

Charging Ontario’s 13% on sales to customers in other provinces, or vice versa, results in under- or over-collection that must be corrected.

Missing the self-employed payment date

Self-employed individuals with a December 31 year-end often assume their annual HST is due June 15 because the return is. Payment is due April 30.

Not reconciling returns to the books

HST returns should tie to your general ledger. If they don’t, something is wrong, either in the books or in the returns.

Director liability for unremitted HST

Because HST collected is held in trust, directors of a corporation can be held personally liable for unremitted amounts, along with interest and penalties, unless they can show they exercised the degree of care, diligence, and skill that a reasonably prudent person would have exercised in comparable circumstances. This is one of the most serious personal risks for directors of small corporations, and one of the strongest reasons to stay current.

Frequently asked questions

How Solstice Partners can help

Solstice Partners handles GST/HST registration, monthly, quarterly, and annual filing, ITC reviews, Quick Method analysis, and catch-up HST filings for businesses across Toronto and the GTA. Because we also handle bookkeeping, your HST returns are prepared from reconciled records and tie back to your books every time.

If you’re unsure whether you should be registered, think you might be leaving ITCs on the table, or have HST returns that need catching up, book a consultation with Solstice Partners.

This article is general information about GST/HST in Ontario current as of October 2026. It is not tax or legal advice for your situation. GST/HST rules, especially place-of-supply, zero-rating, and exempt supply rules, are complex and fact-specific. Consult a qualified professional before making decisions.