GST/HST Number Lookup: How to Check a GST Number

Short answer: to check a GST/HST number, use the CRA’s free GST/HST Registry. You need three things: the first nine digits of the number (leave out “RT0001”), the supplier’s business name, and the date on their invoice. The Registry confirms whether the business was registered on that date. Save the result: it’s your proof that the GST/HST you’re claiming back was charged by a registered supplier.

This guide is for Canadian online sellers who buy inventory, packaging and services from other businesses and claim the GST/HST back. If you haven’t registered yourself yet, see how to register for GST/HST.

When should you check a GST/HST number?

Your situation	Check the Registry?	Why
A new supplier charges you GST/HST on an invoice of $100 or more	Yes	You need their number to claim the input tax credit
A supplier’s invoice shows tax but no GST/HST number	Ask for it, then check	Required on invoices of $100 or more
A large one-off purchase, like equipment or a bulk inventory order	Yes	The CRA can deny a large ITC if the supplier wasn’t registered
A small purchase under $100 from a big retailer	Usually not needed	Under $100 the number isn’t required on the receipt
A Quebec supplier charges you QST	Check the QST number with Revenu Québec	The CRA Registry doesn’t cover QST
A customer asks you to prove your number	Point them to the Registry	Anyone can confirm your registration there

Your GST/HST number, decoded

A full GST/HST number has two parts:

123456789 RT0001
└───┬───┘ └─┬──┘
Business   GST/HST program
Number     account

• The 9 digits are the business’s Business Number (BN). It’s the same for every CRA account the business has.
• RT means GST/HST. Other accounts use other letters, such as RC for corporate income tax and RP for payroll.
• 0001 is the account reference. A business with more than one GST/HST account (for example separate divisions) can have RT0002 and up.

The Registry only asks for the 9 digits.

How to use the GST/HST Registry

1. Open the GST/HST Registry on canada.ca and accept the terms of use. The link is in official sources below.
2. Enter the GST/HST number: the first nine digits only, no spaces or letters.
3. Enter the business name: the supplier’s legal, operating or trading name. If it doesn’t match, try the other names on their invoice or website.
4. Enter the transaction date: the date on the invoice, receipt or contract.
5. Search. The Registry shows whether that number was registered for GST/HST on that date.
6. Print or save the search details screen and keep it with the invoice. The CRA recommends this so you can show your input tax credits only include GST/HST charged by registered suppliers.

The Registry is free and anyone can use it. It has service hours, so it can be unavailable late at night.

If the search fails

A failed search doesn’t always mean the supplier isn’t registered. Check these first:

• Typos in the 9 digits
• The wrong name. A store called “Northshore Packaging” might be registered as “1234567 Ontario Inc.” Ask the supplier for the exact name registered with the CRA
• The date. A supplier who registered last month won’t show as registered for an invoice dated before that

If it still fails, ask the supplier to confirm their details. If they can’t, call CRA Business Enquiries at 1-800-959-5525.

Worked example: checking a packaging supplier

Coastline Ceramics, a Victoria pottery studio, buys $2,400 of shipping boxes and padding from a new supplier. The invoice shows:

Line	Amount
Boxes and padding	$2,400.00
GST 5% (123456789 RT0001)	$120.00
Total	$2,520.00

Before claiming the $120 on its next GST/HST return, the owner searches the Registry with 123456789, the supplier’s name from the invoice and the invoice date. The result confirms the supplier was registered on that date. She saves a PDF of the result in the same folder as the invoice.

Because the purchase is over $500, the invoice also needs Coastline’s name, the payment terms and a description of the goods. It has all three, so the $120 is a valid input tax credit. (BC PST on the boxes isn’t claimable as a GST/HST credit.)

Red flags

• Tax charged with no number. A supplier who charges GST/HST on an invoice of $100 or more must show their number. If they won’t give it, don’t assume the tax is claimable.
• A number that doesn’t fit the format. GST/HST numbers have 9 digits and then RT followed by 4 digits.
• A small supplier charging GST. A business that isn’t registered can’t charge GST/HST. If a seller on a marketplace adds “GST” to your invoice but isn’t in the Registry, that tax isn’t claimable.
• A Simplified GST/HST Registry number. Some foreign digital businesses register under a simplified system and show a different kind of number. They shouldn’t charge GST/HST to a GST/HST-registered business that gives them its number. If you don’t give them yours and they charge you tax, you can’t claim it as an input tax credit. Add your GST/HST number to your account with any foreign software or ad platform that asks for it.

Checking a QST number

The CRA Registry doesn’t check Quebec Sales Tax numbers. For a QST number, use Revenu Québec’s online QST registration validation tool. It works the same way: enter the number and date, and it confirms whether the business was registered.

You only need this if you’re registered for QST yourself and claim input tax refunds, which mostly means businesses based in Quebec. See our Quebec QST guide.

Showing your own number to customers

Once you’re registered, put your GST/HST number on invoices and receipts. Business customers need it to claim credits on purchases of $100 or more. Shopify, WooCommerce and BigCommerce can all print it on order confirmations and invoices: see our Shopify setup guide.

Official sources

• GST/HST Registry: confirming a GST/HST account number, Canada Revenue Agency
• Input tax credits: documentation requirements, Canada Revenue Agency
• Validate a QST registration number, Revenu Québec

Keeping on top of GST/HST?

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