Claiming HST Input Tax Credits on Mixed-Use Property in Ontario

Not every asset a business buys is used only for business. A truck that hauls inventory on weekdays and hauls a boat on weekends. A home office in a building where the owner also lives upstairs. A piece of equipment that serves both a taxable consulting arm and an exempt residential-rental arm of the same corporation. When property serves more than one purpose, the HST input tax credit you can claim has to be apportioned — and getting that split wrong is one of the more common triggers for a CRA adjustment.

This article explains how apportionment works under the Excise Tax Act, the methods businesses commonly rely on, and what happens when the mix of uses shifts after you've already claimed your credit.

What Counts as "Mixed-Use" Property

Mixed-use property is anything — real property, a vehicle, equipment, even a professional's home office — that is used partly to make taxable supplies (the commercial activity that lets you register for HST and claim input tax credits) and partly for something else: personal use, or an exempt activity like long-term residential renting.

The key distinction is between:

• Commercial use — generates taxable supplies, and HST paid on related inputs is generally recoverable as an ITC.
• Exempt use — generates supplies the Excise Tax Act does not tax (for example, renting out a long-term residential unit), and HST paid on related inputs is generally not recoverable.
• Personal use — has nothing to do with the business at all, and is never eligible for an ITC.

A single property or piece of equipment can straddle two, or even all three, of these categories at once.

The Core Rule: You Can Only Claim the Business-Use Share

A registrant can claim an input tax credit only to the extent that the property or service was acquired for use in the registrant's commercial activities. Where use is mixed, CRA expects you to apportion the tax paid on a reasonable basis and claim only the portion attributable to commercial use.

"Reasonable" doesn't mean any number you like — it means a method that genuinely reflects how the property is actually used, applied consistently, and documented well enough to defend if CRA asks.

Common Apportionment Methods

Whichever method you choose, the Excise Tax Act doesn't hand you a formula — it expects the result to be fair and defensible, and it expects you to apply the same method consistently from year to year unless the underlying facts change.

Common Mixed-Use Assets and the Traps They Create

Vehicles. A vehicle used for both business deliveries and personal errands is one of the most heavily scrutinized ITC claims on audit, because mileage logs are easy to demand and hard to reconstruct after the fact.

Home offices and mixed-use buildings. A building with a ground-floor commercial unit and a residential unit upstairs has one taxable use and one exempt use under the same roof — the ITC on shared costs like utilities, roofing, or a shared heating system needs its own apportionment, separate from the routine office-supply purchases the business makes.

Equipment shared across a taxable and an exempt arm of the same business. A corporation that runs both a commercial consulting practice and a residential leasing operation can't simply claim full ITCs on shared equipment or software just because one arm of the business is HST-registered.

When Your Usage Changes: The Change-in-Use Risk

The Excise Tax Act doesn't let you set an apportionment once and forget it. If the proportion of business versus personal or exempt use later shifts in a meaningful way — you convert part of a rental building to your own commercial use, or a vehicle's business use drops significantly — the Act's change-in-use rules can require you to account for the shift, sometimes by treating part of the property as newly acquired or newly disposed of for HST purposes.

These rules are technical and fact-specific, and the thresholds that trigger them are exactly the kind of detail that's easy to get wrong from a general summary. If your mix of use has changed materially, get advice before assuming your original ITC claim still stands.

Documenting Your Apportionment

CRA can ask you to justify an apportionment years after you claimed it. Keep:

• [ ] A written record of the method you used and why you chose it
• [ ] The underlying measurements (floor plans, mileage logs, usage logs, revenue records) that support the percentage
• [ ] Records showing the method was applied consistently, or documentation of why and when it changed
• [ ] Invoices and receipts for the underlying purchase, showing the HST paid
• [ ] Any prior CRA correspondence accepting — or challenging — a similar apportionment

What Happens on Audit

An auditor reviewing a mixed-use ITC claim is typically testing two things: whether your apportionment method is reasonable, and whether your records actually support the percentage you claimed. A method that looks reasonable on paper but has no supporting documentation behind it is treated the same as an unsupported claim — CRA can deny the ITC and reassess.

If CRA denies part of your claim, you aren't without options. You can dispute the reassessment through the same administrative and judicial channels available for any HST dispute: an objection filed with CRA, and, if that doesn't resolve it, an appeal to the Tax Court of Canada.

Frequently asked questions