GST number lookup: the CRA registry needs 9 digits, name and date

What does the GST/HST Registry ask for?

The CRA's GST/HST Registry is free and asks for three pieces of information, all of which sit on the supplier's invoice canada.ca:

Once the search confirms the number, print the Search Details screen and file it with the invoice. The CRA asks you to do this so your client's ITC claims include only tax charged by registered suppliers canada.ca.

When the name you typed returns nothing, the supplier may have registered under a different name. The CRA's advice is to ask the business owner for the exact name they gave the CRA and search again canada.ca. Try the legal name from the bottom of the invoice before you conclude the number is bad.

Which number on the invoice is the GST/HST number?

A CRA program account number has three parts: the nine digit business number, a two letter program identifier, and a four digit reference number. GST/HST accounts use RT, so a typical number reads 123456789 RT0001 canada.ca. A payroll number on the same invoice (RP) or a corporate tax number (RC) shares the nine digits but isn't the GST/HST account. For registering a client's own number, see the business number page.

The simplified list prints each business's legal name, trade name, number, and effective registration and deregistration dates; it was last updated October 13, 2026 canada.ca. The QST rows come from Revenu Québec, which mandates the CRA to administer QST for selected listed financial institutions revenuquebec.ca.

What does a failed lookup cost your client's ITC?

The ITC itself. Where a supplier gave a false or incorrect registration number, the CRA's position is that the purchaser isn't entitled to claim an ITC for that supply (GST/HST Memorandum 8.4, paragraph 24) canada.ca. The memorandum still prints the old $30 band; the registration number is now required from $100 under section 3 of the Input Tax Credit Information Regulations laws-lois.justice.gc.ca.

The legal hook is ETA 169(4)(a): before filing the return that claims the credit, your client must hold evidence containing the prescribed information, and a valid number is part of it from $100 laws-lois.justice.gc.ca. Paragraph 25 of the memorandum leaves room where the error is clerical, because the minister may validate the ITC under the 169(5) discretion canada.ca.

Here is how one quarter plays out for an Ontario client at 13% HST with three supplier invoices:

Your client paid $1,040 of HST and can claim $130 + $650 = $780. Before writing off Supplier C's $260, ask in writing for the correct particulars: a supplier must furnish them forthwith on request to support an ITC claim (ETA 223(2)) laws-lois.justice.gc.ca, and a person who fails to provide information required under the Act faces a $100 penalty for every failure (ETA 284) laws-lois.justice.gc.ca. The other invoice details are on the ITC documentation page.

Why a digital vendor on the simplified list can cost your client tax it never recovers

Foreign digital businesses registered under the simplified GST/HST regime sit on a separate CRA list, not the main registry. If your client is a normal GST/HST registrant buying from one of them, it must give the vendor evidence of its own registration. Otherwise the vendor charges the tax and your client can't claim an ITC or a rebate for it canada.ca.

Say a $100 monthly software plan billed to an Ontario business carries $13 of HST because the account never had a GST/HST number on file. Over twelve months that is $156 your client can never claim back through its return. Give the vendor your client's GST/HST number as evidence of registration before the next invoice is issued.

For your own clients who sell into Canada from abroad, the non resident registration page covers which regime applies.

How do you check a QST number?

The CRA registry doesn't validate QST numbers: confirm those on Revenu Québec's website canada.ca. Revenu Québec runs a Validate a QST Registration Number online service, plus an API for bulk checks (user guide SW-340-V). The API returns the number's status, a description of that status, the effective date, the business name and any commercial name. It needs the full number: ten digits, TQ and four more digits revenuquebec.ca.

NR numbers work differently. Revenu Québec publishes the list of suppliers outside Québec registered under the specified system, 2,217 of them at its October 5, 2026 update revenuquebec.ca. Your client can't claim an input tax refund for QST paid to an NR supplier, even on purchases for its commercial activities. It avoids the tax by giving its own TQ number before the transaction, and QST already paid has to be refunded by the supplier directly revenuquebec.ca. Registration rules for your own Québec clients are on the QST registration page.

What if the registry is down or the supplier won't answer?

The registry runs Monday to Saturday only, because of daily maintenance. In Eastern time it is up from 4:30 a.m. to 3:00 a.m. the next morning on weekdays and from 5:30 a.m. to 5 p.m. on Saturday, so a Sunday search fails canada.ca.

If the supplier won't give you its number, or the registry gives you trouble, call the CRA Business Enquiries line at 1-800-959-5525 to confirm registration canada.ca. Nothing in the Act obliges your client to verify a number, so this is protection, not a filing step (Memo 8.4, paragraph 24) canada.ca. It pays off on new suppliers and large invoices. Most registrants have four years to claim an ITC canada.ca, so check the number before the claim, not years later when the supplier is hard to reach.