"How much is my plex worth?" It's the first question owners of multi-unit properties on the North Shore ask themselves, and it's also the most poorly answered. The value of an income property can't be guessed off the cuff, or read off the tax bill: it's calculated from three recognized methods — comparables (prices actually paid), the income method (capitalization by the cap rate, GRM and NIM multipliers), and the cost method (rebuilding new). For a duplex, triplex or quadruplex, it's above all the net income that dictates the value. This 2026 guide explains how to estimate your plex method by method, what pushes the price up or down, and how to move from a range to a real number.
How much is a plex really worth on the North Shore in 2026?
The value of a plex is not a fixed number carved in stone: it's a range that depends on what an informed buyer is willing to pay today, in your area, for the yield and the precise condition of your building. Two triplexes side by side on the same street can differ in value by CA$80,000 simply because one has market rents and a new roof, while the other has leases frozen for ten years and windows to replace.
For an income property — as opposed to a single-family home — the valuation logic is distinctive: a buyer is first buying an income stream, not living space or a coup de coeur. That's why the net operating income (NOI) and the cap rate weigh more than the number of bedrooms or the colour of the kitchen. A good estimate cross-checks all three methods to reduce uncertainty.
The takeaway in one sentence
For a plex, you almost always start from net income divided by the market cap rate, then validate with the comparable sales in your area and, if needed, the replacement cost. The final number is a range — confirmed by a concrete offer.
What are the 3 methods to estimate the value of an income property?
Certified appraisers rely on three complementary approaches. None is perfect on its own; together, they frame the market value of your multi-unit property.
| Method | Principle | When it dominates |
|---|---|---|
| Comparables | Prices paid for similar properties sold recently | Small plexes (2 to 5 units) in an active area |
| Income | Capitalization of net income by the cap rate; GRM / NIM multipliers | Any income property — the leading method |
| Cost | Rebuild new − depreciation + land | Recent, new or atypical buildings |
How do you estimate a plex with the comparables method (APCIQ)?
The comparables method means looking at the prices actually paid for plexes similar to yours, sold recently in the same area. It's the most intuitive approach and the one the market favours for small multi-unit properties.
What makes a property "comparable"
- The area: a triplex in Sainte-Thérèse doesn't compare to a triplex in Saint-Jérôme — the medians differ.
- The number of units and the typology (duplex, triplex, quadruplex).
- The overall condition and year of construction.
- The level of rents relative to the market.
- The sale date: a transaction from 18 months ago doesn't necessarily reflect today's market.
APCIQ statistics give median trends by region, but to estimate your plex you have to drill down to the area level. Our plex price tools can help you set a realistic first benchmark by income and area (Laval, Terrebonne, Repentigny, Blainville, Saint-Jérôme and more).
Market trends: APCIQ — Quebec real estate market statistics
How do you calculate the value of a plex with the income method (cap rate, GRM)?
This is the leading method for an income property. It starts from a simple principle: a buyer pays for a yield. The more net income the building generates, the more it's worth; the more yield the market demands (a high cap rate), the less it's worth.
Step 1 — Calculate the net operating income (NOI)
The NOI is the building's income once operating expenses are paid, but before the mortgage and depreciation:
- Actual gross income (rents in place + parking, laundry, etc.)
- − Operating expenses: municipal and school taxes, insurance, maintenance and repairs, caretaking, management, owner-paid utilities
- − Vacancy and bad-debt allowance
- = Net operating income (NOI)
Careful: an NOI inflated by forgetting expenses (management, vacancy, maintenance reserve) skews the entire valuation.
Step 2 — Divide the NOI by the market cap rate
The cap rate (capitalization rate) is the net yield the market demands for your type of building in your area. The formula:
Value = NOI ÷ cap rate
Illustrative example: an NOI of CA$33,000 with a market cap rate of 5.5% gives a value of 33,000 ÷ 0.055 ≈ CA$600,000. The same NOI at a 6.0% cap rate drops to CA$550,000 — a CA$50,000 gap for half a point of cap rate. That shows just how sensitive the cap rate is. Our cap rate calculator lets you test these scenarios on your own numbers.
Step 3 — Validate with the GRM and NIM multipliers
The GRM (gross rent multiplier) = price ÷ gross income. If comparable plexes sell at a GRM of 14 and your building generates CA$42,000 in gross income, the GRM estimate is ≈ CA$588,000. It's quick but rough (it ignores expenses). The NIM (net income multiplier) refines it by relying on net income. Use these multipliers as a cross-check on the cap rate calculation, never on their own. The GRM calculator gives you a range in seconds.
When should you use the cost method to value a plex?
The cost method estimates what it would cost to rebuild the building new today, less accumulated depreciation (wear, obsolescence), plus the value of the land. It answers the question: "Would it cost more to build the equivalent than to buy it?"
For an existing plex, this method mainly serves as a safety benchmark: it is dominant for recent, new or atypical buildings (few comparables, unusual income). For a 40-year-old triplex in an active area, it counts less than income and comparables — but it keeps you from paying more for a building than its replacement value.
What raises or lowers the value of a plex?
Beyond the methods, certain value drivers show up systematically in the final price of an income property:
Net income (NOI) — the main engine
Everything starts here. Each extra dollar of NOI, capitalized at 5.5%, adds about CA$18 to the value. Optimizing income and controlling expenses is value lever number one.
Market rents vs. below-market rents
A plex with below-market rents generates a lower NOI, therefore a lower capitalized value today. The upside potential exists, but the buyer discounts it: they factor in the time, the risk and the steps (tenant turnover, oversight by the Tribunal administratif du logement) needed to bring rents up to market. You pay for the rents in place, not the dream.
The building's condition and deferred work
Roof, windows, foundation, plumbing, heating: significant deferred work is deducted from the price, often at the level of the estimated cost (sometimes more, for the risk and disruption). A well-maintained building trades higher and faster.
The area and rental demand
A low vacancy rate, proximity to services and transit, the area's momentum: all of this supports rents and compresses the required cap rate, therefore supports value.
Interest rates
When financing costs rise, buyers demand a higher cap rate for the building to carry itself — which lowers value at a constant NOI. Conversely, lower rates compress cap rates and support prices. Net income and the rate environment are the two dominant levers of a multi-unit property's value.
The municipal assessment roll is not your sale price
- It is used to calculate taxes, not to set a market price.
- It is based on a fixed reference date, often 1 to 3 years out of step.
- It can be well below or sometimes above the real value depending on the area.
- It ignores your leases, the precise condition and current market conditions.
Worked example: how much is a triplex in Terrebonne worth in 2026?
Let's take a fictional triplex in Terrebonne, purely for illustration. Annual gross income: CA$42,000. Here's how the three methods converge toward a range.
Income method (cap rate)
- Gross income: CA$42,000
- Operating expenses (≈ 30%): − CA$12,600
- Vacancy allowance: − CA$1,000
- NOI ≈ CA$28,400
- Market cap rate: 5.5%
- Value ≈ 28,400 ÷ 0.055 = CA$516,000
Cross-check
- Area GRM ≈ 13.5 → 42,000 × 13.5 = CA$567,000
- Area comparables: CA$510,000 – CA$560,000
- Replacement cost: does not cap value here
- Retained range: ~CA$515,000 – CA$560,000
- If rents below market: toward the bottom
- If roof/windows need work: additional discount
The methods don't give an identical number — that's normal. You draw a range from them (here about CA$515,000 to CA$560,000), then adjust it for the actual condition and the rents. These figures are illustrative: they show the method, not the value of your building. To start from your real numbers, begin with a free review of your plex.
What mistakes do owners make when estimating their plex?
Most do-it-yourself estimates go off the rails for the same reasons. Avoid these classic traps:
- Overvaluing on potential rather than on the actual rents in place. The market pays for what is, discounts what could be.
- Forgetting expenses (management, vacancy, maintenance reserve) and artificially inflating the NOI.
- Confusing the municipal assessment with market value.
- Comparing with non-comparable buildings: different area, different number of units, different condition.
- Ignoring deferred work that is deducted from the price.
- Applying an imported cap rate from another market (Montreal, another region) to a North Shore area.
Each of these mistakes can skew the estimate by tens of thousands of dollars — in either direction.
Do you need a certified appraisal, or is a do-it-yourself estimate enough?
It all depends on what you want to use it for.
A do-it-yourself estimate is enough when…
You simply want to position yourself, decide whether a sale or refinance is worthwhile, or negotiate from an informed position. Comparables, the cap rate and the GRM give you a reliable range in a few minutes. To move quickly, combine income-based area benchmarks, the cap rate calculator and the GRM calculator.
A certified appraisal becomes necessary when…
You need a defensible, independent figure: bank financing, a dispute, an estate, a split between partners or co-owners. An appraiser who is a member of the OEAQ then produces a report carrying a professional and legal weight that a do-it-yourself estimate does not — at the cost of a delay and fees.
How do you get an accurate, concrete estimate of your plex?
All the methods above give a range. The only way to turn that range into a real number is a concrete offer. That is exactly what ImmoMulti does: a direct buyer of multi-unit properties on the North Shore — duplexes, triplexes, quadruplexes and income properties — with no broker, therefore no commission. Based on your income, your expenses and the condition of the building, ImmoMulti prices an offer, usually in under 48 hours.
You stay free: the offer gives you a solid benchmark to compare against your own estimate, whether you decide to sell or not. If you want to go as far as receiving an offer on your building, the process is free and with no obligation.
Whether your plex is in Laval, Terrebonne, Repentigny, Blainville, Mascouche, Sainte-Thérèse or Saint-Jérôme, the same logic applies: start from net income, divide by the area cap rate, validate with comparables, adjust for condition — and confirm with a real offer.
Informational content only. Does not constitute legal, tax or financial advice, nor a professional appraisal within the meaning of the OEAQ. All amounts, cap rates, GRMs and ranges presented are provided for illustration and do not constitute a personalized estimate of your building. Consult a certified appraiser for a report carrying professional weight.
Frequently asked questions — Estimating the value of my plex
