How to Register for HST in Ontario
A complete, step-by-step guide to registering your business for GST/HST in Ontario. Knowing when you must register, choosing your effective date, opening your CRA GST/HST account, setting your reporting period, charging the right tax, claiming input tax credits and filing on time, explained in plain language by a licensed CPA so you get it right from the start.
What This Guide Covers
1. Before You Register: What HST Is and Who Must Charge It 2. When You Have to Register 3. Should You Register Voluntarily? 4. Step 1: Choose Your Effective Date 5. Step 2: Open Your CRA GST/HST Account 6. Step 3: Set Your Reporting Period and Method 7. Step 4: Charge HST Correctly on Your Invoices 8. Step 5: Track Input Tax Credits 9. Step 6: File and Remit Your HST Return 10. Common HST Mistakes to Avoid 11. Frequently Asked Questions1. Before You Register: What HST Is and Who Must Charge It
HST, the Harmonized Sales Tax, is the combined federal and provincial sales tax you charge on most goods and services in Ontario. When you register, you collect it from your customers on the CRA's behalf, and you remit the net amount after claiming back the HST you paid on your own business purchases. Getting the setup right from the start keeps you compliant and avoids paying tax out of your own pocket.
| What You Need to Know | Why |
|---|---|
| The Ontario HST rate | Ontario's HST rate is 13%, made up of the 5% federal GST portion and an 8% provincial portion. |
| A business number (BN) | Your GST/HST account is opened as an extension of your business number. If you are incorporated you already have one. |
| Whether your supplies are taxable | Most goods and services are taxable at 13%. Some are zero-rated (0%) or exempt, which changes whether you charge tax and claim credits. |
| Your worldwide taxable revenue | The small-supplier threshold is based on your total taxable revenue, which determines whether registration is mandatory. |
| A record-keeping system | You must keep records supporting the tax you charged and the credits you claimed for at least six years. |
| A way to file returns | Accounting software, the CRA's online filing, or a CPA who prepares and files the return for you. |
HST is one of the easiest areas to get wrong and one of the most reviewed. Charging the wrong amount, missing a filing, or failing to register on time all carry consequences, and the errors compound every period. This is why many business owners hand HST to a CPA from the start rather than learning the hard way. We prepare and file HST returns on a fixed flat fee. HST Return Filing →
We Handle Your HST End to End
Skip the registration paperwork, the reporting-period decisions and the filing deadlines. We register your GST/HST account, set it up correctly, and prepare and file every return so your input tax credits are captured and your remittance is right. Fixed flat fee, licensed CPA firm.
Set Up My HST2. When You Have to Register
Registration is not always optional. The rule turns on whether you are still a "small supplier." Once your taxable revenue crosses the threshold, registration becomes mandatory, and the timing matters.
| Situation | Registration Rule |
|---|---|
| Taxable revenue under $30,000 | You are generally a small supplier and registration is optional, though you may still choose to register voluntarily. |
| You exceed $30,000 in a single calendar quarter | You stop being a small supplier immediately and must register right away; the tax applies from the supply that pushed you over. |
| You exceed $30,000 over four consecutive quarters | You must register, generally by the end of the month following the month you crossed the threshold. |
| Taxi and ride-share drivers | Must register regardless of revenue, from the first fare. |
| Certain other suppliers | Some businesses have specific rules; confirm your situation if you are unsure. |
The $30,000 threshold is measured on your total taxable worldwide revenue over four consecutive calendar quarters, not a single tax year. Many owners watch only the annual figure and miss the rolling test. We track this for you and tell you exactly when registration becomes mandatory. HST Return Filing →
Registering late means you may owe tax you never collected. If you cross the threshold and keep invoicing without HST, the CRA can still assess the tax that should have been charged from your effective date, and you may have to pay it yourself, plus penalties and interest. Watch the threshold closely and register on time.
3. Should You Register Voluntarily?
If you are under the $30,000 threshold you are not required to register, but voluntary registration is sometimes the smarter choice. It comes down to who your customers are and how much HST you pay on your own purchases.
| Reason to Register Early | What It Means |
|---|---|
| You buy a lot of taxable inputs | Registering lets you claim input tax credits on the HST you pay on business purchases, which you cannot do as an unregistered small supplier. |
| Your customers are businesses | Business customers claim back the HST you charge, so it does not cost them anything, and charging it makes you look established. |
| You are close to the threshold | Registering before you are forced to avoids a scramble and a mid-period switch. |
| You want to recover startup HST | Registering early can let you recover HST paid on startup costs, within the rules. |
Voluntary registration is a commitment, not a trial. Once registered, you must charge HST, file returns and remit on schedule, even in periods with little activity. If most of your customers are individual consumers who cannot claim it back, charging HST can make you more expensive than an unregistered competitor. Weigh it before you register, and we are happy to run the numbers with you.
4. Step 1: Choose Your Effective Date
Your effective date is the day you become registered and must start charging HST. It drives everything that follows, so choosing it correctly is the first real decision.
1Identify the date you must register from
If registration became mandatory, your effective date is generally the day you stopped being a small supplier, the supply that pushed you over the threshold. From that date, HST applies to your taxable supplies.
2Consider an earlier voluntary date
If you are registering voluntarily, you can often choose an effective date up to 30 days before you apply, which can help you recover HST on recent business purchases. Choose deliberately rather than defaulting to today.
3Make sure your invoicing matches
From your effective date forward, every taxable invoice must show HST. Line up your invoicing and your bookkeeping so nothing goes out without the tax once you are registered.
The effective date is not just a formality. It sets the first day you owe HST on sales and the first day you can claim credits on purchases. Pick it wrong and you either miss recoverable credits or charge tax you were not yet required to. We help you choose the date that fits your situation. HST Return Filing →
5. Step 2: Open Your CRA GST/HST Account
Once you know your effective date, you open a GST/HST account with the Canada Revenue Agency. This is an RT account, registered under your business number, and it is where you file returns and remit the tax you collect.
1Confirm your business number
If you are incorporated, you already have a business number. If you are a sole proprietor without one, you register for a business number first. The GST/HST account attaches to it as a program account ending in "RT."
2Register the GST/HST (RT) account
Register through CRA My Business Account, the Business Registration Online service, by phone, or with your CPA's help. You provide your effective date, your expected annual taxable revenue and your fiscal year-end.
3Record your GST/HST number
Once registered you receive a nine-digit business number followed by the RT program identifier. This number must appear on your invoices so customers can support their own input tax credit claims.
Your GST/HST number belongs on your invoices. Business customers need to see a valid registration number to claim the HST you charge them. Register, capture the number, and add it to your invoice template right away. We can register your account and configure it correctly as part of setting you up. HST Return Filing →
6. Step 3: Set Your Reporting Period and Method
When you register, the CRA assigns a reporting period based on your revenue, and you choose how you calculate the tax you owe. Both decisions affect how often you file and how much work each return takes.
| Annual Taxable Revenue | Assigned Reporting Period |
|---|---|
| $1,500,000 or less | Annual filing is the default, with an option to elect more frequent filing if you prefer. |
| More than $1,500,000 up to $6,000,000 | Quarterly filing is assigned. |
| More than $6,000,000 | Monthly filing is assigned. |
Separately, you choose how you calculate the net tax you remit. The regular method tracks actual HST collected against actual input tax credits. The Quick Method is a simplified option available to many smaller businesses.
| Method | How It Works |
|---|---|
| Regular method | You remit the HST you collected minus the input tax credits you actually paid on business purchases. Most accurate for input-heavy businesses. |
| Quick Method | You remit a lower fixed percentage of your HST-included sales and generally do not claim ITCs on operating costs. Simpler, and often beneficial for service businesses with few taxable purchases. |
The right method can lower what you remit. For a service business with modest purchases, the Quick Method often leaves more in your pocket than the regular method, while an input-heavy business is usually better off claiming actual credits. This is worth modelling before you elect. We compare both for you and elect the one that fits. HST Return Filing →
Annual filers can still owe instalments. If you file annually but your net tax is significant, the CRA may require quarterly instalment payments through the year, with the balance settled on the annual return. Do not assume annual filing means paying only once. Plan cash flow for instalments where they apply.
Hand HST to a CPA on a Flat Fee
Registration, reporting-period setup, method election, input tax credits and on-time filing, all handled for you. Fixed flat fee, no hourly billing, most AFFORDABLE CPA in Canada for business clients.
Get HST Done For Me7. Step 4: Charge HST Correctly on Your Invoices
From your effective date, every taxable invoice must show HST calculated correctly and display your registration number. Charging the wrong amount, or forgetting the number, causes problems for you and your customers.
| Invoice Requirement | What It Means |
|---|---|
| Apply the 13% Ontario rate | Most taxable supplies to an Ontario customer are charged at 13%. Supplies to other provinces may use that province's rate. |
| Show your GST/HST number | Your nine-digit business number with the RT identifier must appear so customers can claim their input tax credits. |
| Show the tax separately or state it is included | Depending on your invoice style, show the HST as a separate line or clearly state that the price includes HST. |
| Know your zero-rated and exempt supplies | Zero-rated supplies are taxed at 0% and still allow credits; exempt supplies carry no tax and no credits. Applying the wrong treatment is a common error. |
| Charge the customer's province rate where required | For supplies across provinces, place-of-supply rules can change the rate you charge. Confirm the rate for out-of-province sales. |
The HST you charge is not your money. The tax you collect belongs to the CRA and is held on its behalf until you remit it. Treating collected HST as cash flow, then finding you cannot remit at filing time, is one of the most common and most painful HST problems. Keep it separate and remit what you owe.
8. Step 5: Track Input Tax Credits
Input tax credits, or ITCs, are the HST you paid on business purchases that you claim back against the HST you collected. They are the reason registration does not simply cost you money, but only if you track them properly.
| ITC Rule | What It Means |
|---|---|
| Claim HST on business purchases | You can claim the HST paid on expenses used in your commercial activity, from supplies to equipment to eligible overhead. |
| Keep valid supporting documents | Your claim must be backed by proper invoices showing the supplier's GST/HST number and the tax paid. No document, no credit. |
| Some costs are restricted | Certain expenses, such as some meals and entertainment, are limited or not fully claimable. Apply the restrictions correctly. |
| Timing limits apply | ITCs must generally be claimed within set time limits, so do not let old credits go unclaimed. |
| Personal-use portions do not qualify | Where a purchase is part business and part personal, only the business portion of the HST is claimable. |
Clean bookkeeping is what makes your ITCs bulletproof. When every expense is recorded with its HST and a valid receipt, your credits reconcile cleanly and survive a CRA review. Sloppy records mean missed credits and disallowed claims. Clean books and clean HST go hand in hand, and our team keeps both in order when we handle your HST return filing. Bookkeeping Services →
9. Step 6: File and Remit Your HST Return
Filing means reporting the HST you collected and the input tax credits you are claiming, then remitting the net amount, or receiving a refund if your credits exceed what you collected. The deadline depends on your reporting period.
| Reporting Period | General Filing and Payment Deadline |
|---|---|
| Monthly | Return and payment are generally due one month after the end of the reporting period. |
| Quarterly | Return and payment are generally due one month after the end of the quarter. |
| Annual (most small businesses) | The return is generally due three months after your fiscal year-end. Different timing can apply to some individuals. |
Late filing and late payment are penalized separately. The CRA charges a penalty for filing late and interest on any amount paid late, and the interest compounds daily at the prescribed rate. Even a nil return must be filed on time. Set a reminder, or better, automate it. This single deadline is why many owners move HST to a CPA.
You may be in a refund position. If your input tax credits exceed the HST you collected, for example in a startup or investment-heavy period, your return produces a refund rather than a payment. Filing on time gets that money back to you sooner. We prepare and file your return so credits are captured and refunds are not left on the table. HST Return Filing →
10. Common HST Mistakes to Avoid
First-time registrants tend to make the same handful of errors. Each is avoidable, and each can be expensive.
| Mistake | Why It Hurts |
|---|---|
| Registering late after crossing the threshold | The CRA can assess HST from your effective date on sales where you never charged it, leaving you to pay it yourself plus penalties. |
| Not charging HST once registered | From your effective date, every taxable invoice must include HST. Missing it means you owe tax you did not collect. |
| Missing the filing deadline | Late filing carries a penalty and late payment carries daily compounding interest, even on a nil return. |
| Spending the collected HST | Collected HST belongs to the CRA. Treating it as cash flow leaves you short at remittance time. |
| Missing input tax credits | Failing to track HST on purchases means you remit more than you owe and leave money with the CRA. |
| Claiming ITCs without valid receipts | A credit without a proper supporting invoice showing the supplier's number can be disallowed on review. |
| Confusing zero-rated and exempt supplies | Getting the treatment wrong means charging tax you should not, or missing credits you were entitled to. |
| Ignoring the Quick Method option | Many service businesses remit more than necessary by never comparing the Quick Method against the regular method. |
HST mistakes compound silently. Unlike a one-off error, an HST setup mistake repeats every invoice and every period until someone catches it, and the penalties and corrections pile up. The cost of getting HST wrong for a year almost always exceeds the cost of having a CPA handle it properly from the start.
Frequently Asked Questions
Let a CPA Handle Your HST on a Flat Fee
Registration, reporting-period setup, input tax credits and on-time filing, all handled on a fixed flat fee, plus applicable taxes. Most AFFORDABLE CPA for business clients in Canada.
Set Up My HST