GST/HST Registration Guide for Canadian Contractors & Self-Employed (2026)

One of the most common questions from new and growing contractors is: "When do I need to register for GST/HST, and what does it actually mean for my invoices and taxes?"

This guide walks through the rules, the benefits of registering early, the process, and how it affects your day-to-day invoicing as a tradesperson.

The Small Supplier Threshold

You must register for GST/HST if your worldwide taxable supplies exceed $30,000 in any single calendar quarter or over four consecutive calendar quarters.

"Taxable supplies" generally means your revenue from work that is subject to GST/HST (most contractor and service work in Canada).

Example: If in the last 12 months (or a single quarter) your invoiced revenue from plumbing/electrical/roofing/HVAC/etc. work passed $30,000, you are required to register.

You can also register voluntarily at any time, even if below the threshold.

WHY REGISTER VOLUNTARILY (EVEN BELOW $30K)?

• You can claim Input Tax Credits (ITCs) on the GST/HST you pay on business purchases (tools, truck expenses, materials, fuel, software, marketing, etc.).
• Many commercial clients, GCs, and property managers prefer or require suppliers who are registered (they can claim their own ITCs on your invoices).
• It looks more professional and established on proposals and invoices.
• Once you're close to the threshold, registering early avoids a rushed process and potential penalties for late registration.

Many trades register voluntarily once they hit $20-25k in annual revenue for the above reasons.

What Happens After You Register

• You must charge and collect GST/HST on your taxable supplies (most of your invoices).
• You must include your GST/HST registration number on every invoice.
• You file GST/HST returns (monthly, quarterly, or annual depending on your revenue) and remit the net tax (tax collected minus ITCs claimed).
• You can claim ITCs on eligible business expenses.
• You must file returns even if you collected $0 in a period (nil returns).

Failure to register when required, or late filing/remitting, can result in penalties and interest.

How Registration Affects your Invoices

Before Registration

• You generally do not charge GST/HST.
• You should not show a GST/HST number.
• You can still invoice professionally with clear payment terms and e-transfer instructions.

After Registration

• Add your GST/HST number to your business profile in your invoicing tool (it then appears on all invoices).
• Select the correct tax rate for the client's province (or where the work is supplied).
• The tool calculates and shows the tax on each invoice.
• You track collected tax separately from your revenue for filing.

Our free generator and app make this automatic once you enter your number and province.

Registration Process (high Level)

1. Go to the CRA website (canada.ca) and search for "GST/HST registration" or use the "Register for a GST/HST account" service in your CRA My Business Account (or create one).

2. You will need your business details, SIN or BN (Business Number) if you have one, and information about your expected revenue.

3. Many sole proprietors register under their SIN initially; a BN is assigned as part of the process.

4. For Québec, you may also need to register for QST with Revenu Québec (often done around the same time).

5. Once approved, you receive your GST/HST number and effective date. Start charging from that date (or as required).

The process is mostly online and can be straightforward for sole props. If you have employees or more complex structure, it can take longer.

Provincial Sales Tax (PST/RST) Registration

Separate from GST/HST. If you sell taxable goods or provide certain services in BC, SK, or MB, you may need to register as a PST vendor even at lower volumes. Check each province's finance or tax authority website. Alberta and territories have no PST.

Invoicing Tool Implications

Choose a Tool That

• Lets you store your GST/HST (and QST/PST) numbers.
• Applies the correct rate(s) for the province you select per client or per invoice.
• Shows the number clearly on PDFs.
• Produces tax summary reports for filing.

Just Invoice was designed with exactly these Canadian requirements in mind.

When in Doubt

• Track your revenue quarterly.
• If approaching $30k, register (voluntary is low risk, high reward for most).
• Talk to an accountant who works with trades in your province — they can run the numbers on ITCs vs extra admin and advise on timing.
• Use official CRA and Revenu Québec resources (links in the tax guide).

Related Pages

• Canadian Contractor Tax Guide 2026 (full rates, ITCs, what to charge)
• How to Get Paid Faster Canada Contractors
• Contractor Invoice Checklist (includes registration number requirement)
• Provincial pages (Ontario HST, Alberta GST, BC PST, Québec TPS TVQ)
• All trade templates