A multiplex in Toronto is a building, usually a converted or newly built house, split into several self-contained units within the same structure, and since 2023 the City has allowed up to four of them as-of-right on most residential lots, no rezoning application required. That’s a genuine shift from the older rules, which generally capped a standard residential lot at one or two units without a special approval. Whether you’re a homeowner wondering if your property could legally add units, or a buyer evaluating a listing’s redevelopment potential, the zoning, the approval process, and the real cost all shape what a multiplex actually means for that property. This guide covers what Toronto’s zoning permits, how it differs from a garden suite, laneway suite, or basement apartment, what the permit process still requires, and roughly what conversion runs, alongside everything else a Toronto purchase or build involves in our complete Toronto real estate guide.
What Toronto’s zoning actually allows
City Council approved Toronto’s multiplex zoning change on May 10, 2023, and the amendment took effect that May, with the companion Official Plan amendment following in June 2023. Since then, a duplex, triplex, or fourplex, two to four units within a single building, has been permitted as-of-right on virtually every residential lot across the city, replacing a system where anything past a single unit or a legal second suite generally needed a rezoning application and a public hearing.
The picture has grown more specific since then. In June 2025, Council approved a further increase, up to six units, a sixplex, but only within nine specific wards: the former Toronto and East York district, roughly Roncesvalles to the Beaches south of Eglinton, plus Ward 23 in Scarborough North, which had piloted the higher unit count earlier. Staff had recommended the sixplex permission citywide; Council did not adopt it that broadly, so most of Toronto still sits at the four-unit maximum. Separately, in August 2025 the province approved zoning updates for 120 major transit station areas across the city, allowing taller buildings, generally four storeys, six within 200 metres of a transit station or on a major street, on land near transit. That’s a height and storey allowance layered on top of the existing rules, not a distinct unit-count increase specific to the multiplex permission itself, so a property near transit doesn’t automatically get more units than the general rule allows just because it’s near a station.
How a multiplex differs from a garden suite, laneway suite or basement apartment
These are four different tools for adding housing to an existing lot, and confusing them leads to the wrong assumption about cost, process, or what’s even physically possible. A multiplex creates multiple units within the existing house’s envelope, its footprint and structure, through interior reconfiguration, an addition, or a full rebuild on the same site. Our guide to garden suites in Toronto covers a self-contained secondary home built separately in the backyard, permitted as-of-right on most lots regardless of lane access. Our guide to laneway suites in Toronto covers the same idea, but restricted to a lot whose rear or side line touches a public laneway with enough frontage. And our guide to legal basement apartments in Toronto covers converting the existing basement into one additional, code-compliant unit inside the house, the simplest single step toward the same goal a multiplex conversion pursues at a larger scale.
A property can combine more than one of these. A house legally converted to a triplex could still have room for a garden suite in the backyard, subject to its own setback and lot-coverage rules. The four guides are meant to be read together for a property where more than one option is genuinely on the table, not treated as competing answers to the same question.
What the approval and permit process still requires
As-of-right means no rezoning application and no public hearing before Council or the Committee of Adjustment for a proposal that fits within the permitted unit count and the existing zoning envelope. It does not mean permit-free. Every unit still has to meet the Ontario Building Code, real fire separation between units, proper egress, and the other requirements a building permit application checks, and the City still issues that permit through its ordinary review, not an expedited or waived process just because the use itself is allowed.
A property still needs to go through the Committee of Adjustment when a design exceeds what’s actually as-of-right, a height, setback, or lot-coverage variance beyond the zoning envelope, or where a heritage designation or a similar site-specific overlay applies. Our guide to the Committee of Adjustment in Toronto covers how that process runs and how long it typically takes, and it’s the right reference for a multiplex project that can’t fit within the as-of-right rules cleanly. The City has also flagged that a lot’s servicing, whether the existing water and sewer connections can actually support the added units, and its physical configuration, lot size, frontage, and access, can limit whether a specific property can use the permission at all, even where the zoning allows it in principle. None of this is confirmable from a listing description alone; it takes a site-specific check with the City or a planning professional.
Roughly what a multiplex conversion costs
Neither the City nor TRREB publishes an official cost figure for converting a house to a multiplex, so any number comes from renovation-industry pricing rather than a government source, and it should be treated as a starting range, not a quote. Toronto renovation and design-build firms that publish current pricing put hard construction costs somewhere between roughly $250 and $425 per square foot for a standard-finish multiplex conversion as of 2026, with basic finishes toward the lower end and higher-end finishes and systems pushing well past $500 per square foot. Total project cost scales heavily with how many units the conversion adds and how much of the existing structure has to change: a smaller two-unit conversion, closer to a basement-apartment legalization in scope, tends to land in the low hundreds of thousands, while a full three- or four-unit conversion with new kitchens, bathrooms, and separate mechanical systems for each unit commonly runs considerably higher. Separate utility costs add to that; several Toronto renovation firms cite roughly $1,800 to $4,200 per additional unit just for Toronto Hydro to install a separate meter. The honest range for any specific property depends entirely on the starting condition of the house and how many units the final design creates. A contractor’s site visit and a real design price that number for a specific property; a general guide can’t.
Whether development charges apply
Partially, and the split matters for budgeting. Our guide to Toronto development charges covers the full mechanics, but the short version for a multiplex: Ontario’s Bill 23 exempts the first two additional residential units created on a lot from the City’s development charge. A house converting to a triplex, adding two units to the original one, generally clears that exemption entirely. A house converting to a fourplex or a sixplex adds a third, fourth, or further unit beyond that exempt pair, and those additional units are the ones a development charge is more likely to apply to, at whatever the current per-unit rate is for that unit size. Confirming exactly where a specific project lands against that exemption, and what the City’s current rate is for the exact unit type being added, is worth doing before finalizing a multiplex budget, since it’s a real, sometimes six-figure line most homeowners have never had to account for.
Frequently asked questions
What counts as a multiplex under Toronto’s zoning?
A multiplex is a building containing multiple self-contained residential units within a single structure, typically an existing house converted or rebuilt to hold two to four separate units: a duplex, triplex, or fourplex. Since Toronto’s zoning change took effect in May 2023, this is permitted as-of-right on virtually every residential lot in the city, meaning no rezoning application or public hearing is required for a proposal that fits within the allowed unit count and the existing zoning envelope. A building permit and full Ontario Building Code compliance are still required regardless of the as-of-right status.
Can every Toronto property become a multiplex?
No. The zoning permission is broad, but a specific lot’s actual eligibility depends on details the general rule doesn’t cover: the property’s size and frontage, whether the existing water and sewer connections can support the added units, and whether a heritage designation or another site-specific overlay applies. A property that looks like every other house on the street could still run into a servicing or configuration limit that a general zoning lookup won’t show. Confirming with the City for a specific address, rather than assuming the citywide rule applies without exception, is the only way to know for certain.
How is a multiplex different from a garden suite or laneway suite?
A multiplex creates units inside the existing house’s footprint and structure, through interior changes, an addition, or a rebuild on the same site. A garden suite is a separate, self-contained building constructed in the backyard, and a laneway suite is the same idea restricted to a lot with public laneway access. All three can add housing to the same property, and a lot with enough space could potentially support more than one, but they’re different structures with different rules, different permit paths, and different costs, and none of them substitutes for understanding the other two.
Do I need Committee of Adjustment approval to build a multiplex?
Not if the project fits within what’s already as-of-right for the property’s zoning. A Committee of Adjustment application, a minor variance, becomes necessary when a design exceeds the permitted height, setbacks, or lot coverage, or where a heritage designation or a similar overlay applies to the property. A straightforward conversion within the existing envelope skips that step entirely and goes straight to a building permit application instead, which is still required either way. Where a variance is needed, expect it to add real time to the project; our guide to the Committee of Adjustment in Toronto covers how long that process typically takes and what the application involves, since a multiplex that needs a variance runs on a different timeline than one that doesn’t.
Do development charges apply to a multiplex conversion?
Partly. Ontario’s Bill 23 exempts a lot’s first two additional residential units from Toronto’s development charge, so a two-unit addition, a house becoming a triplex, generally owes nothing under this charge. A larger conversion, a fourplex or a sixplex, adds units beyond that exempt pair, and those additional units are generally subject to the City’s development charge at the applicable per-unit rate. Confirming exactly where a specific project falls against the exemption before finalizing a budget avoids an unwelcome six-figure surprise partway through.
What does a multiplex mean for a buyer or seller?
For a buyer, it’s a real factor in a property’s future value: a lot that could legally support a multiplex conversion carries potential rental income or resale upside a single-family lot doesn’t, but that potential is only real once the site-specific eligibility, servicing, lot configuration, any overlay, is confirmed with the City, not assumed from the general zoning rule. For a seller whose property already qualifies or has already been converted, that’s a genuine, documentable feature to name plainly in a listing, backed by the permits and approvals on file rather than a general claim about the zoning. Either way, this is a planning and permit question a City planner or a qualified professional assesses for a specific address, not something a general guide can confirm from a distance.
Whether a specific property qualifies for a multiplex conversion, and what it would actually cost, depends on details a listing description alone can’t answer. Browse current Toronto listings with that potential in mind, or get in touch with our team to talk through a specific property. See our guides to garden suites, laneway suites, and legal basement apartments for the other ways to add units to a Toronto property, and browse the rest of our guides for everything else a Toronto transaction involves.