GST/HST and QST ITC/ITR Documentation for IT Contractors

An input tax credit reduces GST/HST owing. An input tax refund does the same for QST. Both depend entirely on the documentation behind the claim. A legitimate business expense with GST/HST or QST paid on it produces no credit if the paperwork supporting the claim does not meet CRA’s or Revenu Québec’s required fields. This is a distinct problem from expense eligibility, and it is the one that most often surfaces during a review: the expense was real, but the file could not prove it in the form the tax authority requires.

What the Documentation Actually Has to Show

An ITC or ITR claim is not supported by the fact that money left an account. It is supported by a specific set of facts about the purchase: who the supplier was, what was purchased, when, for how much, and how much tax was charged. CRA’s current ITC information table sets three tiers based on the total amount of the sale, including tax:

• Under CAD $100: supplier name, the date of the invoice or the date tax was paid, and the total amount paid or payable.
• CAD $100 to $499.99: the above, plus the GST/HST amount or a statement that tax is included, the tax status of each item if the invoice mixes taxable and exempt supplies, and the supplier’s or intermediary’s GST/HST registration number.
• CAD $500 and over: the above, plus the purchaser’s name or trading name, a brief description of the goods or services, and the payment terms.

These tiers apply to every purchase a business claims an ITC on, not only reimbursed or personally paid expenses. A corporate card charge, a direct bank payment, and a cheque are all held to the same table. The GST/HST filing guide covers how ITCs feed into the net tax calculation on the return; this guide covers what has to be on file to support the claim once it is made. The owner-paid expenses guide covers the reimbursement-specific rules under section 175 of the Excise Tax Act, which layer on top of this same documentation table when a shareholder or employee is reimbursed rather than the corporation paying directly.

QST uses the same value bands, but the fields are not identical. Revenu Québec’s table requires the amount of applicable QST and a description of the property or service even for purchases under CAD $100. For purchases of CAD $100 or more, the supplier’s or intermediary’s QST registration number is also required.

Verifying a Supplier’s Registration Number

A registration number on an invoice is not proof that the number is valid or that it belongs to the supplier who issued the invoice. CRA maintains a GST/HST registry lookup that lets a registrant confirm whether a given number is active and matches the supplier’s legal or trading name. Checking this is not required for every routine purchase, but it matters for larger claims, new suppliers, and any invoice where the registration number looks incomplete or inconsistent with the supplier’s other documents.

An ITC claimed against an invalid or fabricated registration number can be denied even where the underlying expense was genuine and the payment is not in dispute. This comes up most often with newer or smaller suppliers, subcontractors invoicing for the first time, or suppliers who quote a business identifier without confirming GST/HST registration. The registry check should confirm that the supplier was registered for GST/HST on the transaction date.

QST Input Tax Refunds: A Parallel but Separate Requirement

Revenu Québec administers QST input tax refunds under a documentation standard that uses the same dollar bands as the federal ITC table, but with QST-specific fields. A supplier can be registered for GST/HST, for QST, for both, or for neither. A GST/HST number does not validate a QST claim, and a QST number does not validate a GST/HST claim. The bookkeeping should follow the taxes actually charged and the registration numbers shown on the supporting document.

Revenu Québec’s IN-203-V guide sets out the ITR documentation standard. Revenu Québec provides its own service for confirming a supplier’s QST registration status, separate from CRA’s GST/HST lookup. The two registries are maintained by separate authorities. Confirming a supplier in one does not confirm them in the other.

For a Quebec-based IT contractor or consultancy registered for both GST/HST and QST, every purchase potentially generates two separate claims under two separate tax systems, even though Quebec businesses generally file through Revenu Québec. A file that is well documented for GST/HST purposes is not automatically well documented for QST. Where both taxes were charged and both credits are claimed, the support needs the relevant registration number for each tax, and the bookkeeping needs to track both credits separately, even though the underlying purchase and payment are a single event.

There is also a special QST rule for certain suppliers outside Quebec and digital platform operators whose QST registration numbers begin with NR. Revenu Québec states that a QST registrant generally cannot claim an ITR for QST paid to such a supplier or operator, even if the purchase is for commercial activities. The cleaner process is to identify the purchaser as a QST registrant before the purchase is completed, commonly by providing the business’s TQ registration number, so the supplier does not treat the sale as one to a specified Quebec consumer.

Missing or Incomplete Receipts

Receipts get lost. A supplier’s e-transfer confirmation might be the only record of a payment, or a paper receipt might fade or go missing before year-end. When documentation is incomplete, the options are limited but not zero:

• Request a duplicate invoice from the supplier. Most vendors, especially subscription and SaaS providers, can reissue an invoice or receipt on request. This is the cleanest fix and should be tried first.
• Reconstruct from account history. Many software and cloud providers maintain a billing history accessible through the account portal, which can substitute for a lost paper or emailed receipt if it shows the required fields.
• Use a contract or purchase order alongside the payment record. For larger purchases, a signed contract or purchase order combined with proof of payment can support the claim where the documents, taken together, show the required fields.
• Do not claim the ITC or ITR if none of the above is available. Income tax deductibility is a separate evidence question, and alternative records may sometimes support the expense itself. The GST/HST or QST credit should not be claimed without documentation that meets the applicable table. Claiming it anyway and hoping it is not reviewed is not a position a file should be built on.

The pattern to avoid is treating a missing receipt as a bookkeeping inconvenience rather than a documentation gap that affects the credit. A missing receipt on a CAD $40 purchase is usually a low-dollar exposure. A missing receipt on a CAD $4,000 equipment purchase is a real problem if the claim is ever reviewed.

Mixed-Use Purchases: Documenting the Allocation

A purchase used partly for business and partly for personal purposes only supports an ITC or ITR on the business-use portion. The technology equipment and CCA guide covers how mixed-use percentages apply to capital purchases; the same principle applies to the GST/HST or QST paid on the purchase. For an operating expense such as a phone plan that is 60% business use, the ITC or ITR is available on 60% of the tax paid, not the full amount.

The documentation for a mixed-use claim needs two things: the invoice meeting the applicable table for the full purchase, and a brief, dated note of how the business-use percentage was determined. The note does not need to be elaborate. A short explanation kept with the expense record, consistent from year to year unless usage genuinely changes, is enough to support the position if it is questioned.

The Four-Year Claim Window

An ITC or ITR that was available but not claimed on the return for the period it relates to is not lost immediately. Most registrants, including nearly all incorporated IT contractors and consulting firms, can claim it on a later return filed by the due date for the last reporting period that ends within the four-year ITC window. Revenu Québec describes the parallel ITR rule as a four-year period beginning on the filing deadline for the return in which the ITC or ITR could have been claimed.

A shorter two-year period applies to listed financial institutions and to persons whose threshold amounts exceed CAD $6 million for the relevant fiscal years. The exception is more precise than just “large business”: charities and businesses whose supplies, other than financial services, were at least 90% taxable in either of the two preceding fiscal years remain under the four-year limit.

This window matters in two directions. It means a missed ITC is often still recoverable if it is caught in a later review of the books, rather than lost the moment a return is filed. It also means the documentation supporting a claim needs to be kept beyond the filing date. CRA and Revenu Québec generally require GST/HST and QST records to be retained for six years after the end of the year to which they relate, and longer in some situations.

Common Reasons ITC and ITR Claims Get Denied

• A bank or card statement is the only support on file. A statement confirms a payment happened. It does not show what was purchased or the supplier’s registration status, and it does not satisfy the documentation table on its own.
• The registration number is missing on a purchase of CAD $100 or more. This is the single most common gap on subcontractor and smaller-vendor invoices.
• The claim mixes GST/HST and QST without separating them correctly. A combined return that treats a supplier’s single tax line as both credits, when only one tax was charged or only one registration number is supported, produces an overclaim.
• The purchase was from an outside-Quebec supplier with an NR QST number. For QST registrants, that QST generally does not produce an ITR; the issue should be handled with the supplier before purchase where possible.
• The claim is made outside the applicable limitation period. Four years passes faster than it seems across a busy filing history, particularly for annual filers.
• The purchase was personal or mixed-use, and the full amount was claimed. The business-use portion is the only part that supports a credit.
• The same invoice is claimed twice, once under the regular method and once as part of a quick-method calculation, or once by the corporation and once by the shareholder personally on a separate filing.

Building a Documentation System That Holds Up

A workable system does not need to be elaborate. It needs to be consistent:

• Keep the original invoice or receipt for every purchase. Digital images are acceptable if they are legible, complete, accessible, and retained in a reliable format.
• Organize by reporting period, not by expense category alone, so the file for a given GST/HST or QST return can be assembled quickly.
• Reconcile the receipts on file against the books monthly or quarterly rather than at year-end, so gaps surface while they can still be closed with the supplier.
• Flag and verify new suppliers, particularly subcontractors and smaller vendors, before relying on their invoices for a claim.
• Retain the documentation for the full period a claim could be reviewed or made, generally at least six years from the end of the taxation year the record relates to.

Related Articles

• GST/HST Filing After Registration for IT Contractors covers how ITCs feed into the net tax calculation and the quick method election.
• Owner-Paid Expenses, Reimbursements, and Corporate Credit Cards covers the reimbursement-specific ITC rules under section 175 of the Excise Tax Act.
• Technology Equipment and CCA for IT Contractors covers mixed-use allocation for capital equipment purchases.
• QST Registration for IT Contractors in Quebec covers registering for the parallel Quebec system this guide’s ITR rules apply to.

Get in touch if a GST/HST or QST review has raised questions about ITC or ITR documentation, or you want to confirm your current file would hold up to one.