What Is an Input Tax Credit, in Plain English?
When you run a GST/HST-registered business, you charge your customers tax on the goods and services you sell. But you're also paying GST/HST on things you buy in order to run that business — supplies, equipment, software subscriptions, professional fees, and so on.
An Input Tax Credit (ITC) is simply the mechanism that lets you recover the GST/HST you paid on those business expenses. Instead of paying it and forgetting about it, you can claim it back when you file your GST/HST return — reducing the net amount of tax you owe to the CRA.
Think of it this way: you collect tax on behalf of the government, and you pay tax on your own purchases. The ITC system means you're only remitting the difference — the net tax — rather than the full gross amount you collected.
Example: Your business collects $1,000 in GST from clients in a quarter. Over that same period, you paid $400 in GST on business expenses. You remit $600 to the CRA — not $1,000. The $400 is your ITC.
Why Should Business Owners Care?
For many small and medium-sized businesses, ITCs can represent a meaningful reduction in tax liability every single quarter. Ignored or poorly documented, those credits disappear permanently. The CRA requires that you substantiate every ITC claim you make — and if you're ever audited and you can't produce the right paperwork, those claims can be denied, reversed, and penalized.
In short: unclaimed ITCs are money left on the table, and poorly documented ITCs are a liability waiting to happen.
The good news is that the rules are clear. The Input Tax Credit Information (GST/HST) Regulations spell out exactly what documentation you need — and it's tied directly to the dollar value of the purchase.
What Can Be Used as Supporting Documentation?
Before we get to what information must appear on a document, it's worth clarifying what kinds of documents are acceptable in the first place. Under Section 2 of the Input Tax Credit Information (GST/HST) Regulations, the following may serve as supporting documentation for an ITC claim:
- Invoices — the most common document, issued by the supplier
- Receipts — including paper and digital receipts
- Debit or credit notes — used when a price adjustment has been made after the original transaction
- Written agreements or contracts — particularly for recurring or service-based purchases
- Credit card receipts or statements — acceptable where they contain sufficient information
- Any other document that contains the information required under the Regulations
The key word throughout is sufficient information. The document itself matters less than whether it contains the right details — and that's exactly what Section 3 of the Regulations governs.
The Three Tiers: How Much Documentation Do You Actually Need?
The CRA doesn't require the same level of detail for a $12 coffee as it does for a $5,000 equipment purchase. Section 3 of the Regulations establishes a tiered framework based on the total amount of the purchase. The higher the dollar value, the more information your documentation must contain.
The table below summarizes all requirements across the three tiers:
| Requirement | Tier 1 s. 3(a) — Under $100 | Tier 2 s. 3(b) — $100 to under $500 | Tier 3 s. 3(c) — $500 or more |
|---|---|---|---|
| Supplier name or trade name | ✅ Required | ✅ Required | ✅ Required |
| Invoice date (or date tax paid if no invoice) | ✅ Required | ✅ Required | ✅ Required |
| Total amount paid or payable | ✅ Required | ✅ Required | ✅ Required |
| Supplier's GST/HST registration number (s. 241) | ❌ Not required | ✅ Required | ✅ Required |
| Tax amount shown separately or tax-inclusive statement with rate | ❌ Not required | ✅ Required | ✅ Required |
| Status of each supply where mixed (taxable vs. exempt vs. zero-rated) | ❌ Not required | ✅ Required (where applicable) | ✅ Required (where applicable) |
| Recipient's name or trade name | ❌ Not required | ❌ Not required | ✅ Required |
| Terms of payment | ❌ Not required | ❌ Not required | ✅ Required |
| Description of each supply sufficient to identify it | ❌ Not required | ❌ Not required | ✅ Required |
Breaking Down the Tiers
Tier 1 (Under $100)
Keeps things simple. You need the supplier's name, the date, and the total amount paid. A gas station receipt or a coffee shop receipt will typically satisfy this if it's for a legitimate business expense. These are your lowest-friction claims.
Tier 2 ($100 to under $500)
Raises the bar meaningfully. Now the CRA wants to see the supplier's GST/HST registration number, and the tax must be shown as a separate line item — or the receipt must include a statement that the price is tax-inclusive along with the applicable rate. If the purchase involves a mix of taxable and exempt goods, the status of each supply must be identified. Generic receipts that don't break out the tax amount may not be sufficient at this tier.
Tier 3 ($500 or more)
The most demanding tier. In addition to everything Tier 2 requires, your documentation must now include the recipient's name (your business name), the terms of payment, and a description of each supply specific enough to identify what was purchased. A vague receipt that says "merchandise" won't cut it here. This is the tier where a proper invoice — not just a receipt — becomes essentially mandatory.
Practical Takeaways for Business Owners
- Never throw away receipts for business purchases, even small ones. Under Tier 1, even a simple receipt is enough — but you need to have it.
- For any purchase over $100, ask for a proper invoice that includes the supplier's GST number and shows the tax separately. If a vendor can't provide one, that's a red flag worth noting.
- For purchases $500 and over, confirm the invoice includes your business name, payment terms, and an itemized description of what was purchased. A supplier's generic sales receipt almost certainly won't be enough.
- Digital documentation is acceptable, provided it contains the required information. Most accounting software can capture and store compliant records automatically.
- When in doubt, keep more than you think you need. The CRA can reassess returns going back several years. Your documentation needs to hold up not just today, but if you're audited down the road.
A Note on GST/HST Registration
You can only claim ITCs if your business is registered for GST/HST. Businesses with annual taxable supplies under $30,000 may qualify as a small supplier and are not required to register — but registration is often still advantageous because it unlocks the ability to claim ITCs. If you're not yet registered and your expenses are adding up, it may be worth speaking with an accountant about whether voluntary registration makes sense for your situation.
This article is for general informational purposes only and does not constitute legal or tax advice. For guidance specific to your business, consult a CPA or Canadian tax professional.