What Is a GST Number and How to Get One

Find out what a GST number is, why your business might need one, and how to register for it in Canada.

You’ve probably heard the term “GST number” in the past, but what exactly is it, and when do you need one? A GST number is your business’s unique identifier for collecting and remitting the Goods and Services Tax (or the combined GST/HST, depending on your province). It’s part of your CRA Business Number, and it becomes essential once your business makes $30,000 or more in taxable sales in a single calendar quarter or over four consecutive quarters. 

Even if you’re just starting out, registering early can give your business credibility and allow you to claim input tax credits. Getting a GST number is pretty straightforward, and you can apply online through the CRA. 

So in this article, we’ll take a look at GST Numbers and how to get one if you’re just starting out. Let’s go!

What Is a GST Number and Why Is It Important?

A GST number is a unique identifier assigned to businesses by the Canada Revenue Agency (CRA) when they register to collect the Goods and Services Tax (GST) or the combined GST/HST. It’s part of your overall Business Number (BN), and it tells the CRA you’re officially in the business of collecting taxes on your products or services. 

It also allows you to claim input tax credits for the GST/HST you pay on business expenses. Without it, you could face penalties or missed tax benefits, so it’s definitely something worth understanding from day one.

Who Needs to Register for a GST Number in Canada?

Not every business in Canada needs a GST number right away, but if your taxable revenues hit $30,000 in a single calendar quarter or over four consecutive quarters, registration becomes mandatory. This threshold applies to most businesses, including freelancers, consultants, online stores, and service providers. 

Even if you’re below that amount, you can still register voluntarily. Why would you? Because having a GST number allows you to claim input tax credits, basically, you can get back the GST/HST you paid on business expenses. If you deal with corporate clients or government contracts, having a GST number also boosts your credibility. 

However, if you’re running a hobby or making only a few sales here and there, you probably don’t need to worry just yet but understand where your business fits so you can stay ahead of your tax responsibilities.

When Should You Apply for a GST Number?

As we’ve mentioned before, you should apply for a GST number as soon as your business earns, or is on track to earn, $30,000 or more in taxable sales over four consecutive quarters or within a single calendar quarter. This is the point when registration becomes mandatory. However, many small businesses choose to register voluntarily even before hitting that threshold. Why? Because it gives them the ability to claim input tax credits and adds legitimacy when working with suppliers or larger clients. 

If you’re starting out and unsure whether you’ll reach $30,000 quickly, it’s still smart to keep an eye on your revenue and be ready to apply. Waiting too long could mean penalties or interest charges on uncollected GST/HST.

How to Register for a GST Number with the CRA

Registering for a GST number is easier than you might think. You can apply directly through the Canada Revenue Agency (CRA) website, by phone, or even by mail or fax if you prefer old-school methods. 

Most business owners opt for the online option because it’s quick and straightforward. You’ll need your Business Number (BN) first, which you can get during the registration process if you don’t already have one. 

Then, you simply add a GST/HST program account to your BN. During the process, you’ll be asked for basic business information like your legal name, business structure, estimated revenue, and start date. 

Once you’re registered, the CRA will issue your GST number, which includes your BN followed by the suffix RT0001. After that, you’re officially allowed and required to start collecting GST/HST. 

Recent Updates to the GST/HST Process

There have been a few important changes that business owners should be aware of when it comes to managing their GST/HST obligations. Starting October 20, 2025, you’ll be able to access your GST/HST access code directly within your secure online CRA account, instead of waiting for it to arrive by mail or juggling old-school paperwork. This little update should make life easier the next time you need to file.

Also, if your reporting period kicks off in 2024 or later, electronic filing of GST/HST returns is now mandatory. That means no more paper forms or snail mail—everything goes online, helping to streamline the process (and hopefully cut down on paperwork headaches).

Staying on top of these updates ensures you don’t get caught off guard when tax deadlines roll around.

How to Calculate Your Net GST/HST and Input Tax Credits

Now that you’re registered and ready to roll, let’s break down the basics of calculating your GST/HST.

Here’s the simple math behind it:

• GST/HST Collected: This is the total amount of tax you’ve charged your customers on your sales and services for the reporting period.
• Input Tax Credits (ITCs): This is the GST/HST you paid on eligible business expenses, like office supplies, inventory, or even that new printer from Staples.

To figure out how much you owe (or whether you’re getting a refund), subtract your input tax credits from the GST/HST you collected:

Net GST/HST = GST/HST Collected – Input Tax Credits

If the number is positive, you’ve collected more tax than you paid out, so you remit the difference to the CRA. If it’s negative, that means you spent more in GST/HST on business expenses than you collected from customers, and you might be eligible for a refund.

To make life easier:

• Keep thorough records of both sales and expenses (your accountant—and future self—will thank you).
• Hang on to receipts and invoices for at least six years, just in case CRA comes knocking for an audit.
• Many business owners use bookkeeping software like QuickBooks or FreshBooks to keep things organized and take the guesswork out of reporting.

With these steps in hand, you’ll be well-prepared for your first GST/HST return and avoid any tax-time surprises.

Special GST/HST Rules for Non-Resident Digital-Economy Businesses

If your business is based outside of Canada but you sell digital products or services—think software, streaming subscriptions, or online courses—to Canadian customers, there are some extra GST/HST rules you should know.

Since 2021, many non-resident businesses have been required to register for, collect, and remit GST/HST on sales to Canadian consumers, even if they don’t have any physical presence in Canada. This includes platforms like app stores, online marketplaces, and popular SaaS tools.

Here’s what matters most:

• Thresholds Still Apply: If your total taxable sales to Canadian consumers exceed $30,000 over four consecutive quarters, you’re generally required to register.
• Simplified Registration: There’s a streamlined registration specifically for non-resident digital businesses, making it easier to comply without needing a Canadian address.
• Marketplace Operators: If you use platforms like Shopify, Etsy, or Amazon, the platform itself may be responsible for collecting and remitting GST/HST on your behalf, depending on the circumstances.
• Business Customers vs. Individual Consumers: The rules are different if you sell primarily to Canadian businesses. In many cases, GST/HST may not apply, but you’ll need to keep good records to prove it.

If you fall into this category, it’s a good idea to review the CRA rules or talk to an accountant who specializes in Canadian tax for online businesses. Keeping on top of these requirements will help you avoid surprises (and penalties) as your business grows.

What Happens After You Get Your GST Number?

Once you receive your GST number, your business is officially registered to collect and remit GST/HST in Canada. That means you’re now responsible for charging the appropriate tax rate on your taxable sales, issuing proper invoices, and filing regular GST returns with the CRA. Depending on your revenue and reporting frequency, you may need to file monthly, quarterly, or annually. 

You’ll also be able to claim input tax credits for the GST/HST paid on eligible business purchases. It’s important to stay organized and keep track of all sales, expenses, and taxes collected so your filings are accurate and on time. 

A GST number is a unique tax identification number that the Canada Revenue Agency (CRA) gives to businesses when they register to collect the Goods and Services Tax (GST) or the combined GST/HST. It’s basically your business’s way of saying, “Hey, CRA, I’m collecting tax and doing things by the book.” This number is actually part of your overall Business Number (BN), and it helps the government keep track of how much tax you’re collecting and remitting. 

So with that being said, it’s essential to obtain a GST number, so you’re ready to handle the tax side of your business professionally and responsibly.