Building Types | Duplex
The Toronto Duplex: Two Units, the Simplest Multiplex
A duplex is two units in one building. It is the entry point to Toronto's multiplex permissions: the May 2023 multiplex by-law permits up to four units as-of-right in residential Neighbourhoods zones, so two units sit well inside that ceiling. A compliant duplex is a building-permit process, and it requires no parking.
What Makes a Duplex Legal in Toronto?
A legal duplex in Toronto is a building with two dwelling units, one entirely or partly above the other, built or converted under a City building permit. Zoning By-law 569-2013 counts a detached house with a secondary suite as a separate building type, so a house with a basement apartment is recorded as a house with a suite.
Toronto Building says a permit is required to change a single dwelling unit house into a multi-dwelling unit house, even when no construction is planned. Turning an existing house into a duplex goes through its Multiplex Conversion permit, which asks for:
- a site plan or survey with property lines, lot area, building area, coverage and setbacks, and a summary of the zoning rules the design meets;
- floor plans for each level showing existing and proposed uses, smoke alarms, carbon monoxide detectors and plumbing fixtures;
- sections and construction details for floors, walls, roofs, footings, stairs and guards;
- the Application for a Permit to Construct or Demolish, Schedule 1 designer information, and the Rental Renovation Licence Screening Form;
- separate HVAC and plumbing permits when the work includes them.
The fees in force since January 1, 2026 include $56.33 for each new residential unit and $11.53 per square metre of interior alteration work. The design must also fit the zoning, which the sections below cover, and the Toronto multiplex permit process walks through the steps in order.
Sources, read October 22, 2026: Zoning By-law 569-2013, Chapter 800 definitions (as amended by By-law 648-2025), When Do I Need a Building Permit? (modified July 21, 2026) and Multiplex Conversion (modified July 14, 2026).
Key Takeaways
- ✓A duplex is two units, well inside the four-unit as-of-right ceiling, city-wide.
- ✓No parking required for a duplex since February 3, 2022.
- ✓A compliant duplex is a building permit, not a rezoning.
- ✓The form least likely to exceed the zoning envelope.
Most Toronto lots permit more than two units. Check what yours allows before settling on a duplex.
From the City permit register
How many duplexes have actually been applied for
Since January 2024 115 new-build applications whose permit description names a duplex have been filed, across 106 addresses. That is 13.5% of all new multiplex applications in the city.
Counted a different way, 225 new-build projects citywide added 2 new homes. That figure is not the same thing: the City records new homes net of what was demolished, so a duplex replacing a house adds fewer than it contains.
Across the 92 of them that state a declared construction value, the median is $800,000, running from $550,000 at the 25th percentile to $1,000,000 at the 75th. That is the figure the applicant wrote on the application. It is not a sale price, it is not the finished cost of the build, and it excludes the land.
The City has issued 94 of them, taking a median of 61 days from application. That is 20 days faster than the citywide median of 81 days. 21 are still waiting and are not in that median.
New-build projects only, from the City of Toronto's Active and Cleared building permit registers. Conversions of existing houses, added basement suites, laneway and garden suites are counted separately and are not in these figures. See the full permit tracker for the method.
Two Units, Inside the Same Envelope as a House
A duplex does not get a special envelope. It lives inside the same as-of-right rules as any other residential building in the zone: the height overlay, lot coverage, and setbacks. Because two units are easy to fit, a duplex is the form least likely to push a design out of the building-permit stream and into a Committee of Adjustment variance.
That makes a duplex the natural starting point. A conversion that keeps the existing footprint usually fits the envelope cleanly. A side-by-side or stacked new build of two units sits comfortably within the height and coverage the same lot would allow for a single detached house.
No Parking, Since February 2022
Toronto removed most minimum parking requirements at Council in December 2021, in force February 3, 2022. Duplexes, triplexes, and fourplexes require no parking spaces. For a duplex that means you do not have to surrender yard or build a pad to satisfy a minimum. The space stays available for the building, landscaping, or a future rear-yard suite.
Best For
- ✓ A first multiplex: the simplest two-unit form on a residential Neighbourhoods lot.
- ✓ Converting an existing house where keeping the footprint fits the as-of-right envelope.
- ✓ Owners who want a building permit with no rezoning and no public meeting.
Usually Fails When
- ✕ The conversion adds height or coverage that exceeds the envelope and a variance was not planned.
- ✕ The lot sits in a Heritage Conservation District that adds review.
- ✕ Two units leave the project under-built on a lot that could carry three or four.
What To Verify Before Spending Money
- → The residential zone and Neighbourhoods designation for the parcel.
- → Whether the design fits the as-of-right envelope or needs a variance.
- → Whether a third or fourth unit would underwrite better on the same lot.
Where to Go Next
Frequently Asked Questions
What makes a duplex legal in Toronto?
Is a duplex permitted as-of-right in Toronto?
Do I need parking for a duplex in Toronto?
What is the difference between a duplex and a triplex?
Can I convert an existing house into a duplex?
Does a duplex have to fit a special envelope?
Official Sources Referenced
Related reading
Longer pieces on the same question.
Two units may be well under your limit
Most Toronto lots permit more than a duplex. Before you settle on two, check what the by-law allows at your address.
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