Once your GST/HST taxable revenue crosses $30,000 in any rolling 12-month period, you're required to register for a GST/HST number within 29 days. You can also register voluntarily before you hit that threshold if it makes sense for your business.
Here's how to actually do it — online, by phone, and by mail — and what to expect afterward.
What you get when you register
When the CRA registers you for GST/HST, they issue you a Business Number (BN) — a 9-digit number that identifies your business — along with a GST/HST program account number. The full number looks like: 123456789 RT 0001. The "RT" identifies it as a GST/HST account.
If you already have a CRA Business Number from a payroll or corporate account, you're adding a GST/HST program account to the existing BN rather than getting a new one.
What information you need before you start
Have the following ready before you register:
- Your Social Insurance Number (SIN) — for sole proprietors
- Your legal name and home address
- Your business name (if different from your legal name)
- Your business address
- The date your business started
- Your estimated annual revenue
- The date you want your registration to be effective — this is usually the date you crossed the $30,000 threshold, or the date you want to start voluntarily
- A description of your main business activity
Registering online
The fastest way is through the CRA's Business Registration Online (BRO) portal at canada.ca. You don't need an existing CRA account to use it.
- Go to canada.ca and search "Business Registration Online" or navigate to the CRA's BRO service
- Select "Register for a GST/HST account"
- Enter your personal and business information
- Choose your fiscal year end and filing frequency
- Submit — you'll receive your Business Number immediately
The CRA will mail your formal confirmation, including your account number, within a few weeks. You can start using your BN right away.
Registering by phone
Call the CRA Business Enquiries line at 1-800-959-5525, Monday to Friday, 9 am to 6 pm local time. Have your SIN and the information listed above ready. The agent will register you over the phone and give you your Business Number on the call.
Registering by mail
You can complete Form RC1 (Request for a Business Number) and mail it to your nearest CRA tax centre. This is the slowest option — allow several weeks for processing. Use this only if online and phone options aren't available to you.
After you register: what changes
Once registered, you must:
- Charge GST/HST on all taxable supplies from your effective registration date forward
- Show your GST/HST number on all invoices to registered businesses (amounts over $30 require your number)
- File returns on your assigned schedule (annual, quarterly, or monthly)
- Remit the net GST/HST collected (minus your input tax credits) by the applicable deadline
Voluntary registration
If your revenue is under $30,000, you can still register voluntarily. The main benefit: you can claim input tax credits on business expenses you pay HST on — software, equipment, office supplies, professional services. If your clients are GST/HST-registered businesses, they'll claim the HST you charge as an input tax credit anyway, so it doesn't cost them extra.
Once registered, you can use HST Hero to track your GST/HST collected, calculate what you'll owe at your next remittance deadline, and compare the Quick Method against the regular method to see which saves you more.