How much does it cost to build a fourplex in Toronto?

The fourplex has become the flagship of small-scale development in Toronto: four rental units, on one lot, without rezoning. But what does one actually cost? Here are the realistic 2026 planning numbers we use with clients — and the levers that move them.

The headline construction numbers

• New-build fourplex: roughly $325–$425 per square foot of finished space. A typical 3,600–4,400 sq ft four-unit building lands in the $1.2M–$1.8M construction range.
• Conversion within an existing house: often $130–$200 per square foot for reworked existing space — meaningfully cheaper where the structure, ceiling heights and exits cooperate.
• Addition + conversion hybrids: the addition portion prices like new construction; the existing portion like a conversion.

The soft costs people forget

• Architecture and drawings: commonly $10,000–$30,000+ depending on complexity.
• Zoning review, surveys and consultants: a few thousand dollars, front-loaded.
• Permits and municipal fees: variable — but note the big one below.
• Financing carry during construction: budget for interest on the construction facility for the full build duration.

Toronto is subsidizing exactly this building

Toronto has waived development charges on multiplex conversions of up to four units — a saving that can reach tens of thousands of dollars per project — and removed minimum parking requirements across much of the city. Together these two changes take a fourplex that used to be marginal and make it pencil. Programs evolve, so we confirm the current incentives for your address as part of feasibility.

A realistic all-in example

A bungalow acquired around $1M, replaced with a purpose-built fourplex at roughly $1.4M of construction and soft costs, produces four units that in many Toronto neighbourhoods rent for a combined $12,000–$15,000 per month. The result: one property, four rent cheques, new-construction quality with decades of low maintenance ahead, and equity created the day the building is finished.

What moves your number most

• The lot: frontage, depth and services determine unit sizes and construction method.
• Below grade: a basement unit is the cheapest rentable space you can build — if heights and drainage allow.
• Unit mix: family-sized units rent for more per unit; smaller units rent for more per square foot.
• Finish level: durable mid-spec finishes usually maximize return on rental product.