Since 2024, most single-family lots in BC's towns and cities have been legally allowed to hold three, four or six homes, without a rezoning. That changed what's permitted. It didn't change what's profitable. What decides if your lot is worth more as a multiplex than as a house is what new units sell for, what they cost to build, and the fees and margin in between. This calculator runs that math, the same way a builder deciding what to offer you would.
What the rules allow
Bill 44, BC's small-scale multi-unit housing law, requires every municipality of 5,000 people or more to allow at least the following on lots zoned for a single house or duplex:
- 3 units on lots of 280 m² (about 3,014 sq ft) or less.
- 4 units on lots larger than 280 m².
- 6 units on lots larger than 280 m² within 400 metres of a frequent bus stop, meaning service at least every 15 minutes. Near frequent transit, municipalities can't require off-street parking.
Municipalities had to update their bylaws by June 30, 2024. In 2025, Bill 25 closed a loophole that let some cities exclude zones containing any single-family-only lots, with a further compliance deadline of June 30, 2026. The Province's policy manual, updated in January 2026, recommends site standards such as heights of about 11 metres for three storeys. These are minimums, and some cities allow more.
The units can be any mix: a house with a suite and a laneway home, a triplex, a fourplex, or a small townhouse row.
What your city still decides
The Province sets the unit count. Your municipality still sets the rules that decide how much floor area you can build and how it's shaped:
- floor space ratio (FSR)
- height, setbacks and site coverage
- tree protection
- whether some units must be rental
- development charges and amenity fees
Vancouver's multiplex zoning, for example, allows 1.0 FSR, or about 1.23 for zero-emission buildings, with 50% site coverage. It also charges a density bonus contribution on strata multiplexes.
FSR is the number that drives the economics. On a 4,026 sq ft lot, 1.0 FSR means about 4,000 sq ft of building, however many units you split it into. Six units don't mean six times the house. They mean the same floor area in smaller pieces, often at a higher price per square foot.
Check your municipality's zoning bylaw and talk to a designer before relying on any number here.
How a builder values a lot
Builders work backwards from what the finished units will sell for. This is called residual land value. Whatever is left after construction, city charges, financing, selling costs and the builder's margin is the most they can pay for the land.
The default example is a 33 by 122 ft lot (4,026 sq ft) near frequent transit, so six units are allowed. At 1.0 FSR and 92% saleable area, that's about 3,700 sq ft of units, averaging about 620 sq ft each. The assumptions:
- Units sell at $1,100 per sq ft.
- The project costs $525 per sq ft to design, permit and build.
- City charges are $25,000 per unit.
- Financing is 6% of the project cost.
- Sales and marketing cost 3.5% of sales.
- The builder's margin is 12% of sales.
On those numbers, total sales are about $4.07 million, and a builder could pay about $1.03 million for the land. If the house is worth $1.85 million, it's worth about $820,000 more as a house. For the lot to be worth $1.85 million to a builder, the units would need to sell for about $1,366 per sq ft, roughly 24% more than the default.
The project cost default is in line with one Vancouver design-build firm's published March 2026 rule of thumb of about $500 per sq ft for a plex, excluding land, financing and the BC Hydro service. The sale price reflects new multiplex units in east-side Vancouver-type markets after the 2022 to 2026 price decline. Replace both with figures for your area.
Why many lots are still worth more as houses
The grid in the calculator shows how sensitive the answer is. A 10% change in sale prices moves the land value by roughly $340,000 on the default lot, and a 10% change in construction cost moves it by about $220,000.
Change two things and the picture shifts. Use Vancouver's zero-emission floor area (1.23 FSR) and west-side-style prices of about $1,250 per sq ft, and the builder's number rises to about $1.87 million. That's roughly the value of the house.
In 2026, prices for new townhouses and small strata units in much of Metro Vancouver are about 10% to 20% below their 2022 peaks. Construction costs haven't fallen with them. In many established neighbourhoods, that leaves the builder's number below what an owner-occupier will pay for the house as it stands, and the house keeps changing hands as a house.
The law changed what's allowed. The economics decide what gets built, and in 2026 they're tight.
Where the numbers do work
- Bigger or wider lots. They give more floor area and better layouts.
- Higher FSR. Some municipalities allow more than the provincial minimum. Every 0.1 of FSR adds floor area without adding land.
- Cheaper land relative to finished prices. Many Fraser Valley, Island and Interior markets fit this.
- Frequent transit. No parking requirement can save the cost of a garage or parking pad per unit.
- Lower margins. An owner-builder, or a small builder willing to work on a thinner margin, can make a lot pencil that a larger builder can't.
- Lower city charges. The June 2026 federal-provincial agreement included a commitment to cut development charges on multi-unit housing by up to 50% for three years. How that reaches your municipality's small-scale housing fees depends on local bylaws, so ask your city what applies before you budget.
Building it yourself
If you already own the lot, you're not competing with a builder for it. You're deciding whether to sell the house, or become the builder.
The "If you build it yourself" table uses your house value as the cost of the land, because that's what you give up by not selling. It shows what's left after construction, fees, financing and selling costs. In the default example, building leaves about $309,000 less than selling as a house, before income tax. The finished units don't cover the construction cost plus the value of the land you'd be giving up. Where the builder's number is close to the house value, building yourself can come out ahead. It takes roughly two years of work and carries a builder's risk.
Keep in mind:
- Profit from building and selling new units is generally taxed as business income, not as a tax-free gain on your home.
- New units carry GST, charged to buyers.
- You'll need a licensed residential builder and home warranty coverage for the new homes.
Talk to an accountant and a builder before you commit.
Keeping the units as rentals
Holding the multiplex as a rental changes both the financing and the math.
- Five or more units. CMHC's multi-unit programs, including MLI Select for projects meeting affordability, energy or accessibility targets, can offer high loan-to-value ratios and long amortizations.
- Adding a suite to a home you live in. Since January 2025, insured refinancing has been available for secondary suites, based on the property's value including the new suite.
BC's own secondary suite forgivable-loan pilot closed to new applications in March 2025. The federal low-interest suite loan was cancelled in Budget 2025 before it opened. What exists instead is a CMHC-insured refinance of up to 90% of the home's as-improved value, arranged before construction starts.
Rental income is taxable, BC's Residential Tenancy Act applies, and annual increases are capped at 2.3% for 2026 and 2.2% for 2027. Our investor tax stack calculator runs the rental side.
Selling your lot to a builder
Builders look at a few things first:
- lot width and depth
- lane access
- distance to the nearest frequent bus stop
- slope
- protected trees
- services and the BC Hydro connection
- whether any neighbours are selling too
A builder offer based on land value can land above or below the house value. Get both numbers before you decide.
If your lot is also near a SkyTrain station or bus exchange, transit-oriented development rules may allow much more height and density than small-scale housing does. See the TOD zoning calculator.
Mistakes we see with multiplex math
Multiplying the house price by the unit count. Six units share the same floor area. They don't create six times the value.
Using 2022 prices for new units. Most Lower Mainland markets are 10% to 20% lower in 2026.
Leaving out city charges, financing and selling costs. Together they can take 15% or more of sales.
Assuming six units without checking the transit rule. The bus stop needs frequent service, and the lot has to be within 400 m.
Ignoring tax as an owner-builder. Building to sell is usually a business, not a tax-free home sale.
Questions people ask us
How many units can I build on my lot in BC?
In municipalities of 5,000 people or more, lots zoned for a single house or duplex must allow at least 3 units if the lot is 280 m² or smaller, 4 units if it's larger, and 6 units if it's larger than 280 m² and within 400 metres of a bus stop with service every 15 minutes. Your city may allow more, and its own rules set floor area, height and setbacks.
What is Bill 44?
Bill 44 is BC's 2023 law requiring municipalities to allow small-scale multi-unit housing on lots previously limited to single-family homes or duplexes. Bylaws had to be updated by June 30, 2024. Bill 25 in 2025 closed a loophole, with a compliance deadline of June 30, 2026.
Do I need parking for a multiplex?
Not near frequent transit. Within 400 metres of a frequent bus stop, municipalities can't require off-street parking for small-scale multi-unit housing. Elsewhere, local parking rules apply.
Is my lot worth more to a developer?
Only if the finished units would sell for enough to cover construction, fees, financing, selling costs and a builder's margin, with more left over than your house is worth. In much of Metro Vancouver in 2026, that's a close call. Use the calculator with local prices and costs.
How much does it cost to build a multiplex in Vancouver?
One Vancouver design-build firm's March 2026 rule of thumb is about $500 per sq ft of project cost, covering design, permits and construction but not land, financing or the Hydro service. City charges, financing and selling costs come on top.
What is residual land value?
It's what's left for the land after subtracting all development costs and a builder's margin from the expected sales. It's how builders decide what they can pay for a lot.
Are there grants for building a secondary suite in BC?
BC's forgivable-loan pilot stopped accepting applications in March 2025. Insured refinancing for adding a secondary suite has been available since January 2025. The federal low-interest suite loan was cancelled in Budget 2025 before it opened. What exists instead is a CMHC-insured refinance of up to 90% of the home's as-improved value, arranged before construction starts.
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