Property assessment and appeals in Ontario

Under the Assessment Act, "The assessment of land shall be based on its current value" (s. 19 (1)). Current value means the amount the fee simple, if unencumbered, "would realize if sold at arm's length by a willing seller to a willing buyer" (s. 1). MPAC calculates that value and assigns the property to a class, and municipalities apply their tax rates to it.

The Act sets four-year cycles: "After 2020, for each subsequent period consisting of four consecutive taxation years, land is valued as of January 1 of the year that precedes the period by two years" (s. 19.2 (1), para. 5). The Minister can prescribe a different date, and has done so. O. Reg. 282/98, s. 48.6 states that "January 1, 2016 is prescribed as the day as of which land is valued for the 2021, 2022, 2023, 2024, 2025 and 2026 taxation years."

Values still change when a property does. MPAC: "The 2026 assessment is what the property would have sold for on January 1, 2016 – in its current state and condition, including any major changes since then." New construction, additions, demolitions, severances and changes in use are reflected at 2016 values. Market changes since 2016 are not.

As of October 28, 2026, O. Reg. 282/98 (consolidation from September 4, 2026) did not prescribe a valuation date for the 2027 taxation year, and none had been announced in MPAC's news releases. The 2026 Ontario Budget says the government "continues to receive feedback on approaches that could make the property assessment and taxation system more effective."

MPAC mails a Property Assessment Notice when something about a property changes. It does not send one to every owner each year. MPAC: "If your property details or assessed value changes throughout the year, you will receive a Property Assessment Notice at the end of the year to summarize any changes made in our records." Reasons include a new property or roll number, ownership updates, changes to assessed value, classification or tax liability, and school support updates.

For the 2026 tax year, MPAC said in November 2025 that "618,360 properties will receive a Property Assessment Notice" and that these notices "continue to reflect the property's assessed value as of January 1, 2016." The notice shows the assessed value and classification, and it gives the deadline for a Request for Reconsideration.

Since a 2025 amendment, the Assessment Act allows notices to be sent "by electronic means, if the person consents". MPAC said "the option to receive these notices digitally will begin in 2026."

MPAC's online tool, MPAC AboutMyProperty, shows how a property was assessed and the information MPAC has on file, and lets owners compare it with other properties nearby. MPAC says to "Look for your Roll Number and Access Key on your Property Assessment Notice to register." The same tool is used to view notices online and to file a Request for Reconsideration. For rough figures, see the property tax calculator.

When a general reassessment raises a property's value, the increase is phased in. Assessment Act s. 19.1 (3) reduces the current value by 75 per cent of the eligible increase in the first taxation year, 50 per cent in the second and 25 per cent in the third. This applies to the residential, farm and managed forests classes, and O. Reg. 282/98, s. 49 extends it to all other classes. MPAC: "if your assessed value is lower than it was previously, we'll apply that lower valuation immediately." The last phase-in ran from 2017 to 2020, so 2026 taxes use fully phased-in January 1, 2016 values.