Documentation Required to Claim HST Input Tax Credits in Ontario

An input tax credit that looks perfectly legitimate can still be denied on review if the paperwork behind it doesn't meet the CRA's requirements. The CRA is specific about what information has to appear on an invoice or receipt before it will accept an ITC claim — and "I definitely paid it" isn't, on its own, good enough.

This is one of the most common, and most preventable, reasons Ontario businesses lose input tax credits they were otherwise entitled to. The fix is almost entirely about habits: what you ask suppliers for, and what you keep.

Here's what the documentation requirements generally look for.

What the CRA Generally Wants to See

• The supplier's name (or trading name) as it appears on the invoice
• The supplier's GST/HST registration number
• The date of the invoice or receipt
• The total amount paid or payable
• The amount of HST charged, either shown separately or clearly stated as included
• A description of the goods or services sufficient to show they relate to your commercial activity

Why the Registration Number Matters So Much

The supplier's GST/HST registration number is one of the details the CRA checks most closely, because it confirms the supplier was actually entitled to charge HST in the first place. An invoice missing this number, or that appears to be from an unregistered supplier, can put the whole credit at risk even if the underlying purchase was entirely legitimate.

Requirements Can Scale With the Purchase Amount

The CRA's documentary requirements are not identical for every purchase — smaller transactions generally require less detailed information than larger ones. Exactly where those lines fall changes from time to time, so rather than relying on a fixed dollar figure, treat every invoice as if it needs to carry full supplier and tax details, and verify the current thresholds with your accountant or the CRA directly if a specific transaction is borderline.

Good Habits That Prevent Problems

• [ ] Ask suppliers for a proper invoice, not just a payment confirmation, at the time of purchase
• [ ] Check that the HST amount and the supplier's registration number both appear before you file the receipt away
• [ ] Keep digital or paper copies organized by reporting period, not just by expense type
• [ ] Follow up immediately if a receipt is missing required information — it's far easier to fix before the return is filed than after a CRA review begins
• [ ] Retain records for the full period the CRA expects, not just until your return is filed

Digital Payments and E-Transfers Don't Replace an Invoice

Paying a supplier by e-transfer, credit card, or online payment platform is increasingly common, but the payment confirmation itself is rarely enough on its own. These confirmations typically show that money moved and to whom, but not the supplier's registration number, a description of what was purchased, or a clear breakdown of the HST charged. Ask the supplier for a proper invoice or receipt alongside the payment, and keep both together in your records rather than relying on the payment platform's history as your only proof.

What Happens If Documentation Is Missing

If the CRA reviews a return and finds an ITC claim isn't supported by adequate documentation, it can deny that credit, increasing the net tax you owe, sometimes with interest. A pattern of poor documentation across many claims can also prompt a broader, more time-consuming review of your filings overall.

Frequently asked questions