A clear invoice helps a customer pay you and supports their records. For a registered supplier, it should also make the GST/HST treatment understandable without a follow-up email.
Use a complete template
Include your business or trading name, invoice date and number, customer's name, an identifiable description of the work, fees, tax treatment, total due and payment terms. Show your GST/HST registration number where required and make clear whether tax is added or included. An invoice number is useful for tracking even where it is not one of the prescribed ITC fields.
CRA's current ITC documentation table uses these total-sale bands:
- Under $100: supplier name, date and total are the basic listed fields.
- $100 to $499.99: additional tax information and the supplier's GST/HST number are required, including supply status where taxable and exempt items are mixed.
- $500 or more: buyer identification, a description and payment terms are also required.
These are documentation bands, not exemptions from charging tax and not a reason to remove useful details from smaller invoices. CRA's current information table.
Show the arithmetic clearly
For an ordinary Ontario service subject to 13% HST, a $600 fee gives $78 tax and $678 total. The customer can follow the charge without guessing whether the quoted amount included tax.
If items have different tax treatment, identify them separately. If you correct an invoice, retain the original and the adjustment trail rather than silently replacing a document already used by the customer.
Check older saved templates against current rules. The detailed historical CRA memorandum still shows older dollar bands; the current table linked above is the reference used here. The underlying purchase must still qualify for the customer's ITC.
Checked October 20, 2026. See how to check a supplier's registration.
