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Tax guide for Canadians

GST/HST Guide for Small Businesses

Everything you need to know about the $30,000 threshold, when to register, and how Biller tracks it for you automatically.

The Basics

What is GST/HST?

The Goods and Services Tax (GST) is a 5% federal tax applied to most goods and services sold in Canada. In some provinces, the GST is combined with the provincial sales tax into the Harmonized Sales Tax (HST), which ranges from 13% to 15% depending on the province.

As a small business owner, you need to understand GST/HST because once your revenue crosses a certain threshold, you're legally required to register for a GST/HST account with the Canada Revenue Agency (CRA), collect tax on your services, and remit it to the government.

GST-only provinces

Alberta, British Columbia, Manitoba, Saskatchewan, Quebec (QST separate), and the territories charge 5% GST only.

HST provinces

Ontario (13%), New Brunswick (15%), Newfoundland (15%), Nova Scotia (14%), and PEI (15%) use the combined HST. See current CRA rates.

The Threshold

The $30,000 rule explained.

You are considered a "small supplier" if your total worldwide taxable revenue is $30,000 or less over four consecutive calendar quarters. Small suppliers are not required to register for or collect GST/HST.

You lose your small supplier status -- and must register -- in either of these situations:

  • Your revenue exceeds $30,000 over any four consecutive calendar quarters, or
  • Your revenue exceeds $30,000 in a single calendar quarter.

In either case, you must register for a GST/HST account with the CRA and begin collecting tax. This is not optional -- it's a legal requirement.

The key detail most people miss: the four-quarter test is a rolling window. The CRA doesn't just look at your calendar-year income. They look at any four consecutive quarters. So even if your annual income is under $30K, you might cross the threshold if you earned enough in a specific 12-month stretch.

Rolling 4-Quarter Example
Q1 2025 $7,200
Q2 2025 $8,400
Q3 2025 $6,800
Q4 2025 $9,100
4-Quarter Total $31,500
Exceeds $30,000 -- registration required.
Automatic Monitoring

How Biller tracks this for you.

You shouldn't need a spreadsheet to know if you need to register for GST/HST. Biller does the math in real time.

1

Tracks every payment

Every e-Transfer you receive is automatically added to your rolling revenue calculation. No manual entry needed.

2

Calculates rolling quarters

Biller continuously calculates your revenue across all possible 4-quarter windows, exactly as the CRA would.

3

Alerts you early

When you hit $25,000 (83% of the threshold), Biller sends you an alert so you have time to plan for registration.

After the Threshold

What happens when you cross $30,000.

Crossing the $30,000 threshold is not the end of the world -- it's actually a sign your business is growing. Here's what you need to do:

1

Register with the CRA

You must register for a GST/HST account within 29 days of exceeding the threshold. You can register online through CRA My Business Account, by phone, or by mail using Form RC1.

2

Start collecting GST/HST

Once registered, you must charge GST/HST on all taxable supplies. The rate depends on your province -- 5% GST in most provinces, or 13-15% HST in harmonized provinces.

3

Claim Input Tax Credits (ITCs)

The upside of registering: you can now claim back the GST/HST you pay on business expenses. This includes supplies, software subscriptions, and other costs of doing business.

4

File and remit regularly

You'll need to file GST/HST returns (annually, quarterly, or monthly depending on your revenue) and remit the tax you've collected, minus your ITCs.

Watch Out

Common mistakes to avoid.

Only tracking annual revenue

The CRA uses a rolling 4-quarter window, not the calendar year. You could be under $30K for the year but over $30K in a rolling period.

Waiting too long to register

You have only 29 days after exceeding the threshold to register. Late registration can result in penalties and interest on uncollected tax.

Not keeping records

The CRA requires you to keep records of all income for at least 6 years. Relying on memory or email search is a recipe for trouble during an audit.

Forgetting about ITCs

Once registered, many small business owners forget they can claim back GST/HST on their business expenses. This can save you hundreds or thousands per year.

FAQ

Frequently asked questions.

Can I voluntarily register before hitting $30,000?

Yes. Some businesses choose to register voluntarily so they can claim Input Tax Credits on their expenses. This can make sense if you have significant business costs. Once you register, though, you must start collecting tax from clients.

What if I'm not sure whether my services are taxable?

Most services in Canada are taxable, but some are exempt (like certain health and financial services). If you're unsure, check the CRA's list of exempt supplies or consult with an accountant. Biller tracks your total revenue regardless -- it's up to you and your accountant to determine what's taxable.

What are the penalties for not registering?

If the CRA determines you should have been registered, you'll owe the GST/HST you should have collected, plus interest and potential penalties. The penalty for late filing is 1% of the amount owing, plus 0.25% for each month you're late, up to 12 months.

Does Biller replace my accountant?

No. Biller is an income tracking tool, not tax software. We help you know where you stand relative to the GST/HST threshold so you're not caught off guard. For actual tax filing, registration decisions, and complex tax questions, always consult a qualified accountant.

Official CRA Sources

All facts in this guide are verified against official Canada Revenue Agency publications. Last reviewed March 2026.

The information on this page is for general informational purposes only and does not constitute financial, legal, or tax advice. While we strive to keep this content accurate and up to date, we make no guarantees about its completeness or reliability. Always consult your bank, a qualified professional, or the relevant authority for advice specific to your situation. Last updated March 2026.

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