What Is a Harmonized Sales Tax Number?

If you’re starting a business or offering services in a province that uses HST, you may have heard that you need an HST number. But what exactly is it, why do you need one, and how do you get it?

Let’s break it down in plain English so you know exactly what an HST number is, when to register, and how it affects your tax responsibilities.

HST Number:

An HST number is a unique tax identification number that allows your business to collect and remit Harmonized Sales Tax (HST) to the Canada Revenue Agency (CRA).

This number is part of your CRA Business Number (BN) and is required if you’re doing business in provinces like:

  • Ontario
  • New Brunswick
  • Nova Scotia
  • Prince Edward Island
  • Newfoundland and Labrador

If your revenue exceeds $30,000 in a 12-month period, you must register for an HST number. This is known as the small supplier threshold.

🔍 What Does an HST Number Look Like?

Your HST number is part of your 9-digit Business Number issued by the CRA, followed by an account type and a four-digit reference code.

Example: 123456789 RT0001

  • 123456789 = Business Number
  • RT = GST/HST program identifier
  • 0001 = Reference number

📥 How to Get an HST Number

You can register for an HST number online through the CRA’s Business Registration portal or by calling CRA Business Enquiries.

Ways to register:

You’ll need basic details like:

  • Your legal business name
  • Business address
  • Estimated annual revenue
  • Start date of your commercial activity

Once registered, you’ll receive your HST number right away or by mail.

🧾 Why Do You Need an HST Number?

Here’s what having an HST number allows you to do:

  • Charge HST on your sales and services
  • Collect HST from customers
  • Claim Input Tax Credits (ITCs) for HST you paid on business expenses
  • File and remit your HST returns to CRA

Without it, you’re not allowed to collect HST — and that can lead to penalties if you go over the revenue threshold.

🧠 Key Takeaways

  • An HST number is part of your CRA Business Number and required if you exceed $30,000 in sales
  • It allows you to legally collect and remit HST
  • You can register online, by phone, or by mail
  • You’ll use this number for invoicing, filing returns, and claiming tax credits

FAQ’S

Do I need an HST number if I’m under $30,000 in sales?

Not legally required, but you can register voluntarily to claim Input Tax Credits.

Can freelancers or self-employed workers get an HST number?

Yes, freelancers or self-employed workers must register for an HST number if they earn over $30,000 annually. Voluntary registration is also allowed below that threshold.

Is my GST number the same as my HST number?

Yes, it’s the same account under the CRA. Whether you charge GST or HST depends on your province.

Final Words

Understanding what an HST number is — and when to register — is a big step toward being compliant and confident as a business owner. Once you’re registered, don’t forget to charge the right tax rate on each sale.

Use HSTCalculator.onl to make HST calculations easy and error-free — no spreadsheets or math required.

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