The CRA is a rigorous tax collector: to claim an input tax credit (ITC) for GST/HST paid on business purchases, your customer needs an invoice containing specific information, and the required information grows with the purchase amount. Miss one item — for example your GST/HST registration number — and the CRA can deny the ITC during an audit. Compliance therefore starts at invoice issue. In 4invoices, you can add all of this information to the invoice; checking that it's present and correct is up to you.
The three CRA thresholds (supplies after 2020)
Under $100: supplier's name or trade name, invoice date (or date paid if there's no invoice) and total amount paid or payable. $100 to $499.99: in addition, the supplier's GST/HST registration number and the amount of tax — or a statement that tax is included, with the applicable rate(s). $500 and over: in addition, the buyer's name or trade name (or their authorized representative), the terms of payment and a description sufficient to identify each supply. These tiers replaced the old $30 and $150 thresholds.
Business Number (BN) vs GST registration number
The Business Number (BN) is a 9-digit identifier assigned by the CRA. The GST/HST registration number is the BN followed by RT0001 (for example 123456789RT0001). They're different things and often confused. It's the registration number (BN + RT0001) that must appear on invoices from $100. 4invoices does not verify these numbers with the CRA — enter them carefully in your profile.
A description sufficient to identify the supply
From $500, the CRA requires a description sufficient to identify the good or service. 'Consulting' isn't enough; use 'Strategic marketing consulting, 8 hours, ABC project, May 2026'. In 4invoices, you write each line description freely — the precision of the wording is up to you.
The required information on a Canadian invoice
For a sale of $500 or more to a registered business that wants to claim an ITC, the invoice must contain: (1) your name or trade name, (2) the invoice date, (3) the total amount paid or payable, (4) your GST/HST registration number (BN + RT0001), (5) the amount of GST/HST, or a statement that tax is included and the applicable rate(s), (6) the buyer's name or trade name or their authorized representative, (7) the terms of payment, (8) a description sufficient to identify each supply. Under $500, items 6 to 8 aren't required; under $100, only items 1 to 3 are.
In Quebec, for your customer to claim an input tax refund (ITR), the invoice must also show your QST registration number — distinct from the GST number, a 10-digit number followed by TQ0001 — under similar thresholds. In 4invoices, you can put both numbers on the invoice.
The most common error found in audits is an invoice without the supplier's GST/HST registration number. The customer has paid but can't claim the ITC, losing 5% to 15% of the invoiced amount. That's why more and more businesses reject incomplete invoices and ask for a corrected one before paying.
Frequently asked
I'm self-employed with no business number. What do I put on my invoice?
If your taxable supplies don't exceed $30,000 over four consecutive quarters, you're not required to register for GST/HST — so no registration number on the invoice. You invoice without tax and your customers can't claim ITCs on your invoices. Once you exceed the threshold, you must register and show your BN + RT0001 on subsequent invoices.
Can my invoice be electronic or must it be paper?
The CRA accepts electronic invoices, and PDF is the most common format. No electronic signature is required. What matters is being able to produce the invoice as issued to the customer. 4invoices generates your invoices as PDFs; keep a copy in your records.
How long must I keep my invoices?
Generally six years from the end of the tax year they relate to. Keep your invoices and supporting documents, electronic or paper, for that whole period and keep them accessible for your accountant or a CRA audit.
Complete invoices from the first send
6 months free, no credit card. Add your registration number, the tax rate on each line and a precise description, then send the invoice as a PDF.