The CRA is an efficient tax collector: if you want to claim an input tax credit (ITC) for the GST/HST you paid on business purchases, your supplier's invoice must contain 11 specific pieces of information. Miss just one — for example, forgetting the supplier's GST registration number — and the CRA will deny the ITC during an audit. Across three years of retroactive audits, a non-compliant supplier can cost tens of thousands of dollars. CRA compliance therefore starts at invoice issue, not at fiscal year-end. 4invoices structures every invoice to check all 11 boxes from day one.
CRA thresholds for required information
Under $30: seller name, date, total amount — no GST number required on the invoice. $30 to $150: add the seller's GST registration number and the GST/HST amount (shown separately or included with mention). Above $150: all of the above plus buyer name, payment terms and clear description of goods/services. 4invoices applies these rules automatically based on amount, without you having to think about it.
Business Number (BN) vs GST registration number
The Canadian Business Number (BN) is a unique 9-digit identifier assigned by the CRA to each business. The GST registration number is the BN followed by RT0001 (for example 123456789RT0001). They're different things! Many SMBs conflate them. 4invoices distinguishes the two: the BN to identify the business, the GST number (BN + RT0001) for the tax credit. Both appear on the invoice if the business is GST-registered.
Clear description and date of supply
The CRA requires a description sufficiently clear to identify the good or service. 'Consulting' isn't enough — you need 'Strategic marketing consulting 8 hours, ABC project, May 2026'. The date of supply (when the good was delivered or the service rendered) can differ from the invoice date — supply date is what matters for ITC. 4invoices handles both fields distinctly and alerts if the description is too generic for amounts above $500.
The 11 mandatory fields on a Canadian invoice
For a sale above $150 between two GST-registered businesses, your invoice must contain: (1) your business name or trade name, (2) the invoice issue date, (3) the total invoiced including taxes, (4) your GST/HST registration number (BN + RT0001), (5) an indication that GST/HST is included in the total OR the GST/HST amount shown separately with the applied rate, (6) the buyer's name or authorised representative, (7) payment terms (due date, discount), (8) a clear description of each good or service sold, (9) quantity sold per line, (10) the supply date if different from invoice date, (11) for services paid in stages, the progress invoice number and references to prior invoices.
For Quebec ITCs, the invoice must also display the supplier's QST registration number (which is not the same as the GST registration number — it's a 10-digit number followed by TQ0001). Without this number, the Quebec input tax refund (CITR) is denied by Revenu Quebec, regardless of what federal information is on the invoice. 4invoices stores both numbers (BN + RT0001 for federal GST, and XXXXXXXXXX-TQ0001 for Quebec QST) and displays them correctly on every Quebec invoice.
The most common error, the one CRA systematically catches during audits, is the invoice without the supplier's GST registration number. The customer has paid, has received a service or product, but can't claim the ITC. The direct loss to the customer is 5% to 15% of the invoiced amount (the non-recoverable GST/HST). That's why more and more SMBs reject non-compliant invoices and require correct issuance before payment. 4invoices keeps you from being the business whose invoices get rejected.
Frequently asked
I'm self-employed with no business number. What do I put on my invoice?
If your taxable revenue is under $30,000 per year, you don't need to register for GST — so no number to put on the invoice. You invoice without GST and your customers can't claim ITC on your invoices (which is legal and predictable). Once you exceed $30,000, you must register and get a BN + RT0001 to put on subsequent invoices.
Can my invoice be electronic or must it be paper?
The CRA accepts electronic invoices (PDF, XML, EDI) with no difference. PDF is the most common format. Electronic signature isn't required. What matters is document integrity: if the CRA audits, you must be able to produce the invoice as issued to the customer, without subsequent modification. 4invoices stores every issued invoice in its final immutable state, with timestamped issue date.
How long must I keep my invoices?
The CRA requires 6-year retention from the end of the fiscal year the invoice relates to. For capital assets, it's 6 years after asset disposal. 4invoices archives all your issued and received invoices indefinitely — you exceed the legal minimum without thinking about it. Invoices are exportable as PDF or XML for handover to an accountant or to the CRA on request.
Your invoices CRA-compliant from the first send
Free trial. 4invoices applies the 11 mandatory fields automatically and alerts if information is missing for customer ITC.