How Much Does a Toronto Multiplex Cost?

Start with the scope, not a single price

A conversion, an addition and a replacement multiplex have different quantities and risks. Before asking for a price, define the area being built, what is retained, the number of homes and the site work required.

The City’s 2025 monitoring data recorded average applicant-declared construction values of approximately $216,000 for small residential multiplex permits and $1.01 million for new-house multiplex permits. These are historic permit values across differing scopes, not audited final costs or current all-in quotations. See Figure 13 in the City report ↗.

For your property, use an explicit preliminary scope and a range. Replace assumptions with site evidence and comparable contractor pricing as the design develops.

A worked example using the website’s model

The budget calculator’s base multiplex construction assumption is $425 per gross square foot for a four-home new build at the “Considered” specification. Gross area includes all constructed floors, including a basement being built; it is not rentable area.

This is not the full project cost. Other model reserves, permits and charges, ownership setup, applicable tax, land and financing/holding costs are not included in this subtotal. The example does not confirm site fit, permissions, a designed layout or a construction quote. Rates are house planning assumptions checked September 25, 2026; read the budget assumptions for the complete model.

What does that mean per home?

For this illustration, construction alone is $1.70 million ÷ four homes = $425,000 per home. The selected works subtotal is $2.445 million ÷ four = $611,250 per home, before the omitted items.

Always state which cost you are dividing. For a conversion, distinguish all resulting homes from net new homes. For a combined project, separate the principal building and ADU construction quantities before showing a whole-project average. A lower average does not establish that the funding or monthly cash flow works.

What if construction costs increase?

In the 4,000-square-foot example, increasing the construction allowance by 10% raises construction from $1.70 million to $1.87 million. If the same model percentages apply, services become $93,500, design and consultants $280,500, and contingency $400,700. With the $40,000 demolition allowance unchanged, the selected works subtotal becomes $2,684,700.

That is $239,700 above the base subtotal, before the same omitted items. This is a sensitivity exercise, not a predicted price increase. It shows why changing construction also changes allowances calculated from it.

Run separate scenarios for area, specifications and timing. Keep contingency separate from a known scope change: once a cost is identified, put it in the scope and reassess the remaining reserve. Use the financing guide to test whether extra cost also creates a cash-flow gap.

What moves the budget?

• How much gross area is built, and how much can be retained.
• Excavation, shoring, structural work and unexpected existing conditions.
• Access for construction and the complexity of service upgrades.
• Home count, kitchens, bathrooms, finishes and building systems.
• Approval work, project duration and financing conditions.

Keep a dated assumptions list. Show a base case, then change one major input at a time. Obtain a measured scope and contractor review before treating an allowance as a commitment.

Test the property and the budget together

Use the budget calculator to explore assumptions, then screen the address. A useful next study compares a workable physical option with the owner’s available capital and goals.

The Property Strategy Report includes a concept construction budget and roadmap. Optional Realist financial modelling is separate; it can test financing and rental assumptions against the same physical scope. Neither a headline construction price nor a cost-per-home figure is an investment return.