Ontario Property Tax: How MPAC Calculates Your Bill

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MPAC — the Municipal Property Assessment Corporation — is the independent body responsible for assessing all properties in Ontario. It uses the Current Value Assessment (CVA) method, which is theoretically meant to reflect what a property would sell for on the open market at a specific valuation date. The critical detail: Ontario’s current assessments are still based on January 1, 2016 values. The last province-wide reassessment was in 2016 and subsequent reassessments have been deferred repeatedly. This means assessed values in many areas are significantly lower than current market values — a $1.2M home today might carry a CVA of $800K.

MPAC uses over 200 data points, but five factors account for the vast majority of your assessed value:

Location — neighbourhood, school zone, proximity to transit and amenities

Lot dimensions — frontage, depth, and total lot area

Living area — above-grade square footage of the structure

Age and renovations — build year, and any permitted improvements that MPAC has on file

Construction quality — building materials and structural grade

One practical note: unpermitted renovations generally won’t raise your assessment — but they carry their own legal risks at resale.

The formula is straightforward:

Annual Tax = Assessed Value × (Municipal Rate + Education Rate)
Example: $800,000 assessed value × 0.67% combined rate = approximately $5,360/year in property tax. Rates vary significantly by municipality — Toronto sits around 0.66%, Brampton is closer to 1.0%, and some outer regions exceed 1.2%. Two similar homes priced the same can have very different annual tax bills simply because of where they are.

Not necessarily — and this surprises many people. The municipal budget is largely fixed, so reassessment is revenue neutral at the system level. What changes is how the tax burden is distributed among property owners. The key rule:

Your assessment rose more than the municipal average → your share of the tax burden increases

Your assessment rose less than the average → your relative share decreases.

If your home’s value jumped 40% but the city average also jumped 40%, your tax bill barely moves. It’s relative change that matters, not absolute numbers. This is widely misunderstood.

Arthur’s Note

Property Tax Assessment Flow

Here’s your pre-purchase property tax checklist:

① Visit aboutmyproperty.ca to look up the assessed value and tax history of any property

② Factor the annual tax into your ownership cost model — divide by 12 and add to your monthly budget

③ If the assessed value seems inflated or incorrect, you have 60 days from the assessment notice to file a Request for Reconsideration with MPAC at no cost

④ Use a large assessment gap (assessed value well below asking price) as supporting data in price negotiations — it’s not a direct lever but it adds context to the conversation

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