Use the CRA's free GST/HST Registry. Enter the first nine digits of the number (leave off the RT0001), the business name exactly as it appears on the invoice, and the invoice date. If the business was registered on that date, the registry says so. Print or save that result. If you claim input tax credits on GST/HST you paid, a number you never checked is your risk, and the CRA can take the credit back.
Why would a freelancer need to check a GST/HST number?
Two reasons, and both cost money if you skip them.
The first is the tax you pay. If you're registered for GST/HST, you claim back the tax on your business expenses as input tax credits: the subcontractor you hired, the designer who built your logo, the co-working space. Those credits only count when the business that charged you the tax was registered. If it wasn't, the CRA can disallow the credit at audit, and add interest on top.
The second is your own number. Your clients claim input tax credits on what they pay you, and a careful client's bookkeeper will look you up. If your number doesn't match the name on your invoice, you're the one getting the email.
How do you use the CRA GST/HST Registry?
Search "GST/HST Registry" on canada.ca or go to canada.ca/gst-hst-registry. You need three things from the invoice:
- The first nine digits of the GST/HST number. No letters, so
123456789, without theRT0001. - The business name, as it's printed on the invoice or shown at the place of business. The legal, operating, or trading name all work.
- The transaction date, which is the date on the invoice, receipt, or contract.
The registry tells you whether that business was registered for GST/HST on that date. Print the Search Details screen or save it as a PDF, and file it with the invoice. If the CRA ever asks why you claimed the credit, that page is your answer.
What if the GST/HST number doesn't check out?
Hold the tax portion until it's sorted, and check the name first. It's the common culprit. A numbered company that trades as "Northside Design" can fail if the invoice says one name and the CRA has the other on file.
Email the supplier and ask for the exact name they registered with the CRA, then search again with that name. If the invoice has no GST/HST number at all and the supplier charged you tax anyway, ask for it in writing. If you still can't confirm the registration, the CRA's Business enquiries line (1-800-959-5525) can check it for you.
A supplier who charged you GST/HST and can't show a valid registration owes you an explanation before they get the tax part of the payment. That's an awkward email to send, but it's a lot cheaper than losing the credit.
When does an invoice need the supplier's GST/HST number?
The CRA's rules for input tax credits scale with the size of the purchase. On a purchase of $100 or more, the invoice needs the supplier's GST/HST registration number for you to claim the credit. At $500 and up, it also needs your name, the payment terms, and a description of what you bought.
So a receipt for a $40 lunch with a client doesn't need a number, and a $1,200 invoice from a subcontractor does. The bigger the invoice, the more it's worth the 30 seconds to check.
How do you check a QST number in Quebec?
Separately. The CRA's registry only covers GST/HST and can't validate a QST number. Revenu Québec runs its own free service, "Validate a QST Registration Number", on its website. It works the same way: the number, the name, and the date. If you buy from Quebec suppliers and claim input tax refunds on QST, check both numbers.
How do you make sure your own number passes a client's check?
Run yourself through the registry once. Use the first nine digits of your own number, the business name you print on your invoices, and today's date. If it fails, check the name first: update your invoices to match what the CRA has, or update the CRA's record through your business account so your trading name is on file.
Then make sure the full number, with RT0001, prints on every invoice where you charge tax. Our guide on putting your GST/HST number on invoices covers where it goes, and if you're not registered yet, how to get a GST/HST number takes one session with the CRA. Not sure you need one? Start with whether you have to charge GST under $30,000.
In Loot you enter your GST/HST number once in your account settings, and it prints in the sender block of every invoice and quote PDF. It's Canadian, built for freelancers, and free to start.
Frequently asked questions
How do I check if a GST/HST number is valid in Canada? Use the CRA's free GST/HST Registry on canada.ca. Enter the first nine digits of the number without the RT0001, the business name as shown on the invoice, and the invoice date. It confirms whether the business was registered for GST/HST on that date.
What happens if I claim an input tax credit and the supplier's GST/HST number is invalid? The CRA can disallow the credit and charge interest. Without a confirmed registration you can't claim input tax credits on the GST/HST you paid, so check the number before you claim and keep a copy of the registry result.
Why does a GST/HST number fail the registry check? The most common reason is the business name. The registry matches the number against the name the CRA has on file, so a trade name or a numbered company name can fail. Ask the supplier for the exact name they registered and search again.
Do I need the supplier's GST/HST number on every receipt? No. For input tax credits, the supplier's GST/HST registration number is required on purchases of $100 or more. Purchases under $100 need the supplier's name, the date, and the amounts, without the number.
Can the CRA GST/HST Registry check a QST number? No. The CRA's registry only covers GST/HST. Revenu Québec runs its own free "Validate a QST Registration Number" service for Quebec Sales Tax numbers.
This is general information and not tax advice. Checked against the CRA's GST/HST Registry guidance and Revenu Québec's QST validation service. For a specific situation, talk to an accountant or call the CRA.