A GST number is your business's GST/HST account number: your 9-digit business number (BN) followed by RT and a 4-digit reference, for example 123456789 RT0001. So it is not quite the same number as the BN: it is a program account attached to the BN. You get one by registering for GST/HST with the CRA, or with Revenu Québec for most Quebec businesses.
What is a GST number?
A GST number identifies your business as registered for GST/HST. It has 15 characters: the 9 digits of your business number, the letters RT (the GST/HST program code) and a 4-digit reference number, most often 0001. You see it on invoices from registered businesses, carriers included.
In Quebec, the QST has its own number: 10 digits followed by TQ and a 4-digit reference, for example 1234567890 TQ0001. A registered Quebec business often shows both numbers on its invoices.
Is a GST number the same as a business number?
Not exactly. The 9-digit BN identifies the business to the CRA. Each program account adds two letters and a reference to the BN: RT for GST/HST, RP for payroll deductions, RC for corporate income tax, RM for import-export. Your GST number starts with your BN, but it only exists once you register for GST/HST.
| Identifier | Format | Used for |
|---|---|---|
| Business number (BN) | 9 digits | Identifying the business to the CRA |
| GST/HST account | BN + RT0001 | Collecting and remitting GST/HST, claiming ITCs |
| QST account (Quebec) | 10 digits + TQ0001 | Collecting and remitting QST |
| Import-export account | BN + RM0001 | Clearing goods through customs on import or export |
If you ship to the United States, the RM account is the one that matters at customs: our guide on business numbers for shipping to the USA separates those identifiers.
Do you need a GST number?
According to the CRA, registration generally becomes mandatory once your taxable supplies exceed $30,000 in a single calendar quarter or over four consecutive calendar quarters. Below that you are a small supplier and registration is optional. Some activities follow different rules, such as taxi and ride-sharing.
Registering voluntarily has an upside: a registered business can generally claim input tax credits (ITCs) for the GST/HST it pays on business expenses. In exchange, it has to charge the tax and file returns.
Thresholds, exceptions and tax treatment change and depend on your situation. Confirm the current rules with the CRA or Revenu Québec, and talk to your accountant before registering or claiming ITCs.
Where to find your GST number
- In CRA My Business Account, under the RT program account.
- On the confirmation letter you received when you registered.
- On your previous GST/HST returns.
- In Quebec, in Revenu Québec My Account for businesses, which also administers GST for most Quebec businesses.
To check a supplier's number before claiming an ITC, the CRA offers an online GST/HST registry search, and Revenu Québec lets you validate a QST number.
Why it matters when you ship
Shipping is a business expense like any other. If your business is registered, the GST/HST, and the QST in Quebec, paid on your labels can generally be claimed as ITCs or ITRs for the share tied to your taxable activities. Keep the invoices: they carry the supplier's registration number, which you need to support a claim.
How to tax the delivery charges you pass on to customers depends on what you sell and where you deliver. That is a question for your accountant, not for a carrier.
Compare carriers on MesColis
In MesColis, the billing section of your account settings has an optional field for your GST/HST/QST number. With a free account, no contract and no minimum volume, you compare the carriers that serve your lane side by side before you buy the label.