How to Register for HST After Incorporating in Ontario
Do You Need to Register for HST After Incorporating in Ontario?
Yes, and if your business has crossed (or expects to cross) $30,000 in taxable revenue, you’re legally required to. Here’s the short version:
Once you incorporate in Ontario, HST registration isn’t automatic. You need to separately register with the Canada Revenue Agency, either online, by phone, or by mail. If you’re already at the $30,000 threshold, you have 29 days from the day you exceeded it to register. If you’re not there yet, you can register voluntarily, and there are good reasons to do so early.
The rest of this guide walks you through exactly how to do it, what it costs, and what to watch out for.
What Is HST and Why Does It Matter for Ontario Corporations?
HST (Harmonized Sales Tax) is the 13% tax applied to most goods and services sold in Ontario, 5% federal GST combined with 8% provincial component.
As a corporation, you’re responsible for:
- Collecting HST from your customers on taxable sales
- Remitting that HST to the CRA on a regular schedule
- Claiming input tax credits (ITCs) on HST you paid for business expenses
That last point is why even small businesses register early. Once you’re HST-registered, you can recover the HST you paid on things like software subscriptions, equipment, office supplies, and contractor invoices. That adds up fast, especially in the early months when startup costs are high.
When Do You Have to Register for HST in Ontario?
The $30,000 rule is what most people know, but the details matter.
Mandatory registration is triggered when:
- Your total taxable revenue exceeds $30,000 in a single calendar quarter, or
- Your total taxable revenue exceeds $30,000 over four consecutive quarters
Once you cross that threshold, you become a “registrant” in the eyes of the CRA and must register within 29 days. If you collect HST without being registered, you’re in violation, even if it was unintentional.
A few important notes:
- The $30,000 threshold applies to your worldwide taxable supplies, not just Ontario sales
- Some supplies are exempt (residential rent, medical services, financial services) and don’t count toward the threshold
- If you’re incorporated but haven’t yet made any sales, you’re still considered a small supplier until you hit the threshold
Voluntary registration is available to any incorporated business, even those well below $30,000. Most advisors recommend it early, especially if you’re billing other businesses who expect to see a valid HST number on your invoices.
How to Register for HST After Incorporating in Ontario (Step-by-Step)
Before you can register for HST, you need a Business Number (BN) from the CRA. If you don’t have one yet, you’ll register for both at the same time.
Option 1: Register Online — Business Registration Online (BRO)
This is the fastest and most common route.
- Go to the CRA’s Business Registration Online portal.
- Sign in with your CRA My Business Account, or continue as a new registrant
- Enter your Business Number (or register for one first if you don’t have it)
- Select “GST/HST” as the program account you want to open
- Enter the effective date of registration, this is important
- Complete your business details: legal name, address, fiscal year-end, expected revenue
- Submit — your HST number (BN + RT extension) is typically issued within a few business days
On the effective date: You can backdate your registration to your incorporation date or to when you first started making taxable sales. This matters if you’ve already been collecting HST informally or if you want to claim ITCs on early expenses.
Option 2: Register by Phone
Call the CRA Business Enquiries line at 1-800-959-5525. Have your incorporation documents and BN ready. An agent will set up your HST account directly. Good option if you have questions or want to talk through the effective date.
Option 3: Register by Mail
Download and complete Form RC1 (Request for a Business Number and Certain Program Accounts). Mail it to your nearest CRA tax center. This takes the longest, allow 4–6 weeks. Only go this route if the other options genuinely aren’t accessible.
What Does HST Registration Cost?
This is the refreshing part: HST registration itself is completely free.
The CRA does not charge a fee to register for a GST/HST account. There are no government fees, application costs, or processing charges.
That said, here’s where costs can come in:
| Typical Cost | |
| HST registration (CRA) | Free |
| Accountant to register on your behalf | $100–$300 one-time |
| Bookkeeping software for HST tracking | $20–$60/month |
| Accountant to file HST returns (annual) | $200–$600+ depending on complexity |
| Late registration penalty (if applicable) | varies based on net tax owed and filing period — consult CRA or your accountant |
For a complete breakdown of all incorporation costs read our cost to incorporate in Ontario guide.
Bottom line: The registration itself costs you nothing. The real cost of HST is administrative, staying on top of what you’ve collected, what you owe, and filing on time. Setting up a simple system from the start (even just a spreadsheet) makes the whole thing far less painful.
What Happens After You Register?
Once your HST account is active, a few things change immediately:
You must start charging HST on taxable sales. The moment your registration is effective, every eligible invoice needs to include 13% HST. You can’t choose to not charge it, it’s a legal obligation.
You’ll be assigned a filing frequency. The CRA assigns your reporting period based on your annual taxable revenue:
- Annual filers — under $1.5 million in taxable revenue
- Quarterly filers — $1.5 million to $6 million
- Monthly filers — over $6 million
Most newly incorporated Ontario businesses start as annual filers. You can request a more frequent filing period if you prefer to remit smaller amounts more regularly (useful if you’re claiming large ITCs).
Your HST number goes on your invoices. Format: your 9-digit BN followed by RT 0001 (e.g., 123456789 RT 0001). Clients — especially other registered businesses — will ask for this.
You can start claiming Input Tax Credits. Keep receipts for every business expense that included HST. These offset what you owe when you file.
Common Mistakes to Avoid
After helping Ontario business owners through incorporation and HST registration, these are the mistakes that come up most often:
Waiting too long to register. If you’re already invoicing clients and crossing $30,000, you’re on a 29-day clock. Missing it means penalties and the awkward task of going back to clients to collect HST retroactively.
Choosing the wrong effective date. If you pick a date too early, you’re obligated to have collected HST from that point, even if you didn’t. If you pick too late, you miss out on ITCs. Get this right.
Not separating HST from revenue. HST you collect isn’t your money, it belongs to the CRA. A lot of new business owners spend it and then scramble at filing time. Set it aside from day one.
Forgetting to file even when you owe nothing. Your HST return is due whether you collected HST or not during the period. A nil return still needs to be filed, and missing it attracts penalties.
Frequently Asked Questions
Does incorporating in Ontario automatically register me for HST?
No. Incorporation and HST registration are two separate processes with the CRA. Incorporation happens through the Ontario Business Registry or Corporations Canada. HST registration happens through the CRA’s GST/HST program. You need to do both.
Can I register for HST before I start making sales?
Yes. Voluntary registration is available to any incorporated business regardless of revenue. Many businesses do this at incorporation so they can immediately claim ITCs on startup expenses
What if I’ve been operating without an HST number and already crossed $30,000?
Register immediately. The CRA can assess back taxes, interest, and penalties — but voluntary disclosure before they catch it tends to result in more favorable treatment. Talk to an accountant if you’re in this situation.
Do I charge HST to clients outside Ontario?
It depends on where the supply is made and what type of supply it is. Generally: Ontario-based clients get 13% HST. Other provinces get their applicable rate. International clients may be zero-rated. Speak to an accountant if you have out-of-province clients.
Can I cancel my HST registration if my revenue drops below $30,000?
Yes, but only if you’re a small supplier. You can apply to cancel your registration, but there are conditions — and you may need to remit HST on business assets at the time of cancellation.
HST Registration in Ontario — Key Takeaways
- HST registration in Ontario is free, the only costs are administrative and compliance-related
- You must register within 29 days of crossing $30,000 in taxable revenue; registering voluntarily before that is always an option
- The fastest way to register is through the CRA’s Business Registration Online portal, where your HST number can be issued in a few business days
- Once registered, HST goes on every eligible invoice, and you must file returns on your assigned schedule even if you owe nothing
- Backdating your effective date to your incorporation date lets you claim ITCs on startup expenses, don’t miss that window
Need help with the step before this one? If you’re still working through how to incorporate your business in Ontario, Bizincs handles your entire incorporation online — from NUANS name search to Certificate of Incorporation — all-in from $500. Start your incorporation today →
