Updated Checked by the Tax-Services.ca editorial team How we check
A GST number lookup in Canada means checking a supplier's GST/HST account number in the CRA's GST/HST Registry, a free online tool. You enter the first nine digits of the number, the business name and the date of the sale, and the registry tells you whether that business was registered on that date. People also call it an HST registry search, an HST verification or a GST confirmation, and it is the same tool every time.
HST registry search: how to confirm a GST number in a minute
To confirm a GST number or run an HST verification, enter the first nine digits, the business name and the sale date into the CRA's GST/HST Registry. It shows whether the business was registered on that date. The steps and what each result means are below.
- Find the number on the invoice and copy only the first nine digits.
- Open the CRA's page on confirming a GST/HST account number and start the registry search.
- Type the nine digits, the business name as printed on the invoice and the date of the sale.
- Read the result against the table below.
- Save a screenshot or a note with the date next to the invoice.
| What you see | What to do |
|---|---|
| Registered on the sale date | The GST/HST confirmation is done. Pay the invoice and file your proof. |
| No match | Recheck the digits, the name and the date. A swapped digit is the usual cause. |
| Still no match | Ask the supplier to confirm the number in writing before you pay the tax. |
| No number on the invoice | Ask for it. A supplier who charges tax should be able to give one. |
| Quebec sales tax (QST) | The registry doesn't cover it. Contact Revenu Québec. |
What does a GST/HST number look like?
A GST/HST number is a CRA program account number. The CRA's page on program accounts says these numbers have three parts, and it shows the GST/HST account as 123456789 RT 0001.
| Part | Example | What it is |
|---|---|---|
| Business number (BN) | 123456789 | The business's unique 9-digit number |
| Program identifier | RT | The two letters the CRA uses for the GST/HST program account |
| Reference number | 0001 | Four digits that tell apart accounts of the same type |
That is why the registry asks for the first nine digits: they are the business number. If you only have a short number from an invoice, start with those nine digits. The steps above show what to enter and how to read the result.
Source: CRA, Program accounts you may need.
How to do a GST lookup in Canada
Have the invoice or receipt in front of you. You need three things, and the registry is strict about the format.
| What to enter | How to enter it |
|---|---|
| GST/HST account number | First nine digits only, no letters |
| Business name | Legal, operating or trading name, as on the invoice |
| Transaction date | The date on the invoice or receipt |
Invoices often print the number with letters and more digits after the first nine. Leave all of that out. A full number looks like 123456789 RT 0001, and only the 123456789 part goes in the box. If the supplier hasn’t put a number on the invoice, ask for it. You can also call the CRA business enquiries line at 1-800-959-5525 when you can’t find it.
The CRA’s own page on confirming a GST/HST account number sets out the same steps, and it explains the point of the exercise: to help make sure your input tax credit claims only include tax charged by someone who is registered.
Why bother checking a supplier’s number?
If your business claims input tax credits, the GST/HST you claim must have been charged by someone who was registered. The CRA built the registry for that reason. A fake number on an invoice can put your claim at risk, and you’d find out only after a review.
Is it worth doing for every invoice? No. Check new suppliers, large invoices and anything that looks odd, like a number with the wrong number of digits or a business that only sends text messages. For your regular electricity provider, skip it.
Say Marcus, who runs a small landscaping firm in Barrie, gets a $4,000 invoice from a contractor he has never used. The invoice shows $520 of HST. That’s $520 he plans to claim back. A thirty-second lookup before he pays is cheap insurance next to losing that credit later.
What if the registry says the number isn’t valid?
First, check your typing. A transposed digit is the most common reason. Then check the name against the invoice and the date against the day of the sale, since the tool matches all three. If it still comes back empty, go back to the supplier and ask them to confirm the number in writing.
If they can’t, think hard about paying the HST at all. You can’t claim a credit for tax charged by someone who wasn’t registered when they charged it, and a business that adds a tax line without a valid number is a red flag in its own right.
What the registry can’t tell you
The registry confirms registration. It doesn’t say whether the business is honest, whether it charged the right amount, or whether it filed its returns. The date matters too, because a business can be registered today and not have been on the day of your purchase. That’s why the tool asks for the transaction date.
Quebec adds a wrinkle. The CRA page says QST can’t be checked there, so for the Quebec part you contact Revenu Québec directly. And if you’re an individual shopper with no business, you rarely need any of this. You pay the tax shown on the receipt, and what you can do is work it out yourself with the GST and HST calculator to see whether the total looks right.
Common mistakes with a GST lookup
The first is checking once and never again. A supplier registered last year may have cancelled since, so check new suppliers and check again when a large claim depends on the answer. The second is using today’s date instead of the invoice date. The third is trusting a number just because it is printed on the invoice. Anyone can print nine digits.
Keep a screenshot or a note of each check, with the date, next to the invoice. If the CRA ever asks about a claim, you can show what you did.
Checking every supplier is not realistic, and nobody expects you to look up a coffee shop. The check earns its keep when you claim input tax credits, when the invoice is large, or when someone you have never heard of asks you to pay tax on a handshake deal.
Checking the tax on an invoice
A quick sum catches most errors. Take an Ontario invoice of $1,000 before tax. HST at 13% is $130 and the total should be $1,130. In Alberta the same invoice carries $50 of GST and totals $1,050. In Saskatchewan it’s $50 GST plus $60 PST, for $1,110.
If the invoice only shows the final total, the reverse HST calculator backs the tax out. In the three provinces with a separate provincial tax, use the GST and PST calculator instead. Quebec has its own GST and QST calculator.
What do the digits in a GST/HST number mean?
A full number such as 123456789 RT 0001 has three parts. The first nine digits are the business number, which the CRA uses to identify the business across all its accounts. "RT" marks the GST/HST account, and the last four digits are a reference number for that account. That's why the registry only asks for the first nine digits: the business number is the part that identifies who you're checking.
Once you know this, a few oddities stand out on an invoice. A number with only eight digits is a typo or a fake. A number that ends in something other than "RT" followed by digits belongs to a different CRA account, such as payroll, not to GST/HST. If the invoice shows a nine digit number and nothing else, you can still look it up, since the registry never needed the rest.
What if customers ask for your own number?
The lookup works both ways. If you're registered, your own customers may check you, so print your full GST/HST number on every invoice where you charge the tax, and spell the business name exactly as it appears on your registration. A mismatch between a trade name on the invoice and the legal name on the CRA record is one of the most common reasons a customer's check fails, and it's an easy thing to avoid.
If you aren't registered because you're under the small supplier threshold, don't invent a number and don't add GST/HST to your prices. Tell customers plainly that you aren't registered. A short line on the invoice does the job and saves them a lookup that would only come back empty.
When a business has to register at all
Lookups come up because some businesses don’t have a number. The small supplier threshold is $30,000 of taxable sales, measured over four consecutive calendar quarters or in any single quarter, and a business under it doesn’t have to register or charge GST/HST. That’s the usual reason a small seller, a freelancer or a hobby business has no number on the invoice. Once a business goes over, the CRA’s general information guide for GST/HST registrants says it must register within 29 days of the sale that took it over the line.
If a supplier does charge GST/HST but can’t give you a number, be careful and ask. A small supplier who hasn’t registered has no right to add the tax to your bill. Some sectors have their own rules, so check the details for your own situation on canada.ca before you register or decide not to.
A quick checklist before you pay a new supplier
When an unfamiliar business sends an invoice with GST/HST on it, run through a short list before you pay. It takes a few minutes and covers most of the risk.
- Is there a number on the invoice, and does it start with nine digits?
- Does the business name match the name you entered in the registry?
- Did you use the date of the sale, and today's date stays out of it?
- Does the tax add up? On a $1,000 Ontario invoice, HST at 13% is $130 and the total is $1,130.
- Did you save a screenshot or a note of the result next to the invoice?
If every answer is yes, pay and file the invoice. If one answer is no, fix that item first. A missing number means you ask the supplier for it, and a mismatched name means you ask what name the registration is under.
Worked example: Marcus checks the $4,000 invoice
Go back to Marcus, the Barrie landscaper. His contractor's invoice shows $4,000 of work and $520 of HST. He first checks the sum. HST at 13% on $4,000 is $520, so the tax line is right and the total should be $4,520.
Next he types the first nine digits of the number, the contractor's name as printed on the invoice and the invoice date into the registry. Suppose it comes back empty. Marcus rechecks his typing, finds he swapped two digits, and tries again. This time the registry confirms the business was registered on the date of the sale. He saves a screenshot, pays the invoice and keeps the note in his records, so the $520 he plans to claim has a paper trail behind it.
The sources behind this page
The lookup steps and the nine digit rule come from the Canada Revenue Agency‘s page on confirming a GST/HST account number. The example rates use the 2026 federal and provincial rates in our data, which come from CRA and provincial pages. This site has no link with the CRA and can’t look numbers up for you, so use the registry itself.
Frequently asked questions
How do I confirm a GST number?
Enter the first nine digits of the GST/HST number, the business name and the date of the sale into the CRA's GST/HST Registry. It shows whether the business was registered on that date.
What does an HST registry search not show?
It confirms registration only. It doesn't say whether the business is honest, charged the right amount or filed its returns, and it can't check QST.
What should I do if the GST number does not verify?
Check the digits, the name and the sale date first. If it still fails, ask the supplier to confirm the number in writing before you pay the tax.
How do I look up a GST number in Canada?
Use the CRA GST/HST Registry. Enter the first nine digits of the account number, the business name and the date of the sale.
Why does my GST number check fail?
Usually a typo, a trade name that differs from the legal name, or a date outside the time the business was registered. Ask the supplier for the exact registered name.
Is a GST verification the same as a GST lookup?
Yes. Both mean checking a supplier's number in the CRA registry. It confirms registration on the date you enter, not that the business is honest or that the tax is right.
- GST, HST, PST and QST explained for every province
Which GST, HST, PST or QST applies where you shop or sell in Canada, the 2026 rates for every province, who must register and how to add or remove tax