How to Register a Business in Ontario: Business Registration, Incorporation, GST/HST, Business Number & Startup Guide (2026)

Starting a company is exciting, but figuring out how to register a business in Ontario correctly is what keeps that excitement from turning into paperwork headaches later. Whether you are opening a home-based shop in Oakville, launching a consulting practice in Mississauga, or building a tech startup in Toronto, Ontario business registration follows a fairly predictable path once you understand the steps.

This guide walks through business structures, the Ontario Business Registry process, incorporation, your CRA business number, and GST/HST registration, so you can start a business in Ontario the right way in 2026.

If you are looking for a quick snapshot of the fees and timelines required by the Ontario Business Registry (OBR), here is what to expect:

Registering a business in Ontario means formally recording your business name and structure with the provincial government through the Ontario Business Registry (OBR).

If you plan to operate under any name other than your own full legal name, provincial law requires you to register that name under the Business Names Act. This applies to sole proprietorships, partnerships, and corporations alike. Registration gives your business legal standing, lets you open a business bank account, and is usually the first document a bank, supplier, or client will ask to see.

Step 1: Choose Your Business Structure

Before anything else, decide whether you will operate as a sole proprietorship, a partnership, or a corporation. This choice affects your taxes, your personal liability, and how much the registration will cost, so it is worth thinking through carefully rather than defaulting to whatever seems fastest.

Step 2: Search Your Business Name

Search the Ontario Business Registry to confirm your proposed name is not already taken. Corporations need a NUANS report to confirm the name does not conflict with existing registered businesses or trademarks across Canada. Sole proprietorships and partnerships are not legally required to order a NUANS report, but a quick search still protects you from rebranding costs later.

Step 3: File Through the Ontario Business Registry

Create an Ontario.ca account and an Ontario Business Account, then select the correct transaction  Register a Sole Proprietorship, Register a Partnership, or Incorporate a Business Corporation. You will need your legal name, business address, a description of your activities, and a NAICS code that best matches your industry.

Step 4: Get Your Company Key and Confirmation Documents

Once your filing is processed, you will receive a Business Name Registration (formerly known as a Master Business Licence) for a sole proprietorship or partnership, or Articles of Incorporation for a corporation. You will also be issued a Company Key a unique code you will need for any future filings, renewals, or updates in the registry, so store it somewhere safe.

Choosing the right business structure in Ontario comes down to liability, taxation, and how much complexity you are willing to manage.

• Sole proprietorship: The simplest and cheapest structure, but you are personally liable for every business debt.
• Partnership: Shared ownership and shared liability between two or more people, with income reported on each partner’s personal tax return.
• Corporation: A separate legal entity that protects your personal assets, taxed at the corporate rate, and generally the better fit once your business earns beyond roughly $50,000 to $70,000 a year.

A Business Number (BN) is a nine-digit federal identifier issued by the Canada Revenue Agency (CRA). It connects your business to its CRA program accounts, including GST/HST, payroll, corporate income tax, and import-export.

If you incorporate through the Ontario Business Registry, your Business Number is usually assigned automatically as part of that filing. If you register a sole proprietorship or partnership, you may need to apply for your business number separately with the CRA, depending on which program accounts your business needs.

Ontario charges a 13% Harmonized Sales Tax (HST) on most goods and services. You are required to register for and start charging GST/HST once your revenue passes $30,000 over four consecutive calendar quarters, or in any single quarter.

Below that threshold, you are considered a small supplier and registration is optional. Many small businesses choose to register voluntarily anyway, since it allows you to claim Input Tax Credits (ITCs) and recover the HST you pay on business purchases and startup expenses.

• Registering a confusingly similar name: Registering a name that is too close to an existing brand can force a costly legal dispute or rebrand later.
• Missing the Initial Return deadline: New Ontario corporations must file an Initial Return within 60 days of incorporation to confirm director and address details, a step many new owners overlook.
• Forgetting the 15-day update rule: Failing to update your information in the OBR within 15 days of any change, such as a new business address or director change.
• Confusing structure protections: Assuming a sole proprietorship name registration gives you the same name protection as a corporation—it does not.
• Delaying GST/HST registration: Waiting too long after crossing the $30,000 threshold, which can force you to remit taxes retroactively out of your own pocket.
• Losing the Company Key: Losing track of the Company Key needed for routine filings, address updates, and renewals.

The steps above cover the mechanics of Ontario business registration, but choosing the right structure, timing your GST/HST registration, and setting up your CRA accounts correctly from day one is where most new business owners want professional guidance.

Tax Square Professional Corporation is a CPA-led accounting firm serving Mississauga, Oakville, Milton, Toronto, and the wider Greater Toronto Area. The team helps entrepreneurs choose between a sole proprietorship and a corporation, handles the Ontario Business Registry filing and NUANS name search, and registers a CRA Business Number along with GST/HST, payroll, and corporate tax accounts in a single appointment. You can learn more or book a free consultation at taxsquarepc.ca.

1. How long does it take to register a business in Ontario?

Online filings through the Ontario Business Registry are usually processed immediately for sole proprietorships and partnerships. Incorporation typically takes one to three business days when filed online.

2. How much does it cost to register a business in Ontario?

A sole proprietorship or partnership costs $60 to register. Provincial incorporation costs $300, and federal incorporation costs $200 plus any applicable Ontario extra-provincial registration fees.

3. Do I need a business number if I already have a Business Name Registration?

Yes. A Business Name Registration (formerly a Master Business Licence) is a provincial name registration, while a Business Number is a separate federal identifier from the CRA used for tax, payroll, and GST/HST filings.

4. When do I need to register for GST/HST in Ontario?

You must register once your revenue exceeds $30,000 over four consecutive quarters or in a single quarter. Many businesses register voluntarily earlier to claim Input Tax Credits.

5. Should I choose a sole proprietorship or incorporate my business in Ontario?

A sole proprietorship is cheaper and simpler to start, but offers no liability protection. Incorporation costs more upfront but protects personal assets and can reduce your tax burden once income grows, which is why many entrepreneurs consult a CPA before deciding.