How a Multi-Unit Mortgage Works When You Live in One Unit

A buyer called us last spring about a fourplex. Good job, 10% saved, and a plan to live in the back unit and rent the other three. His bank had already told him it was a rental purchase, and rentals need 20% down.

That was not the whole story, and it nearly cost him the property.

A multi-unit mortgage on a duplex, triplex or fourplex is not the same file as a rental purchase, and it is not the same file as buying a regular house either. It sits in between. Live in one of the units and doors open that most buyers never hear about. Live somewhere else and a different rulebook applies. Knowing which one you are under before you write an offer decides how much you need down and how much you can borrow.

What a Multi-Unit Mortgage Covers, and Where the Line Is

Two to four units is still residential lending. The same lenders, the same insured programs, the same qualifying math you would see on a house. Five units or more crosses into commercial, where the building's income carries the loan and the down payment jumps. If you are looking at a fiveplex or bigger, our guide to a commercial mortgage in Calgary covers that world instead.

Inside the two-to-four-unit band, there are two versions of the same building:

• Owner-occupied. You live in one of the units. Default insurance is available, the down payment can be small, and rent from the other units can help you qualify.
• Non-owner-occupied. Nobody in the family lives there. It is a rental purchase, and the numbers are tighter.

That single choice changes the down payment, the price cap, the amortization and how much rent counts. It is also a declaration you sign. Buying a rental on an owner-occupied program is mortgage fraud, and lenders do check.

One more distinction worth clearing up. A house with a basement suite is usually still a one-unit property with a suite attached, not a legal duplex. The rules for suite income are their own thing, and we cover them in the guide to a secondary suite mortgage. A true duplex is two registered dwelling units.

Down Payment: Why Two Units and Three Units Are Different Files

This is the part almost nobody gets right, and it is where that fourplex buyer was given the wrong answer.

On an owner-occupied purchase with default insurance, the maximum loan is set by unit count:

• One or two units: up to 95% of the lending value. That is 5% down on the first $500,000 and 10% on the portion above it.
• Three or four units: up to 90% of the lending value. That is 10% down.

Put real numbers on it. A $700,000 duplex you plan to live in needs $25,000 on the first $500,000 plus $20,000 on the next $200,000, so $45,000 down. The same $700,000 price on a triplex needs $70,000. Same price, same buyer, $25,000 apart because of one extra door.

A few conditions ride along with the insured purchase program rules:

• The purchase price has to stay under $1.5 million. At or above that, insurance is off the table and you are into conventional financing with at least 20% down.
• Amortization generally caps at 25 years on an insured file, with a 30-year option available to first-time buyers and on new builds.
• At least one borrower needs a credit score of 600 or better.
• The insurance premium is added on top of the mortgage. Our guide to mortgage default insurance walks through how the premium is calculated and when it is worth paying.
• A borrowed down payment from an unsecured loan or line of credit is only allowed on one and two unit homes in the highest loan-to-value band. On a triplex or fourplex, expect the lender to want saved or gifted funds with a clean paper trail.

How Lenders Count the Rent on a Multi-Unit Mortgage

Here is the second half of the surprise. Rent from the units you are not living in can be added to your income, but how much of it counts also moves with the unit count.

On an owner-occupied two-unit property, up to 100% of the gross rent from the other unit can be used, and some lenders will also take the property taxes and heat out of your debt ratios.

On an owner-occupied three or four unit property, the lender picks one of two approaches: up to 50% of the gross rent, or a net rental calculation that takes gross rents minus operating expenses.

Read those two together and something useful falls out. Moving from two units to three raises your down payment and cuts how much rent counts. On paper, a duplex is often the easier qualifier, even though a fourplex collects more rent. That is not an argument against a fourplex. It is an argument for running the math on both before you fall in love with a listing.

Lender policy on top of that is genuinely all over the map. Some add a percentage of the rent to your income. Some offset it against the property's own payment instead, which gives a different result. Some cap how many rental properties you can hold. Some will not touch a single-unit rental but are comfortable with two to four units. This is one of the clearest cases where sending the file to the right lender matters more than shopping the rate.

However the lender counts it, they want the rent proven:

• Signed leases for the occupied units. Month-to-month tenancies may need a tenant acknowledgement or a few months of bank statements showing the deposits.
• An appraiser's opinion of market rent, which is what gets used for a unit that is vacant or that you plan to rent after closing.

What Underwriters Check Before They Fund a Multi-Unit Purchase

The property gets more scrutiny than a single-family house does. Expect questions on all of this:

• Are the units legal? Permits, registered units and municipal records have to line up with what the listing claims. An unpermitted fourth unit usually means the file gets underwritten as a triplex, or gets declined.
• Zoning and local rules. Municipalities differ on what is allowed and how many units a lot can carry. Your lawyer and the city are the authority here, not the seller's listing.
• The appraisal. Plan on a full appraisal with a market rent addendum. In smaller markets, comparable sales for a triplex or fourplex can be thin, and a weak appraisal shrinks the loan.
• Existing tenants. Leases and damage deposits transfer with the building, so you cannot assume a unit will be empty for you on possession day. Provincial tenancy rules decide when a tenant can be given notice for an owner to move in, and the timelines are longer than most buyers expect.
• Condition and insurance. Older multi-unit buildings often carry older wiring, older plumbing and shared systems. The insurer's answer becomes the lender's answer, so get a quote early.

Confirm all of it during your condition period rather than after possession.

If You Are Not Living There, It Is a Different Program

Buying two to four units purely as a rental changes the file again. On the insured route for rental properties, the minimum equity is 20%, the loan tops out at 80% of value, the property value has to stay under $1 million, and amortization caps at 25 years. Outside that you are into conventional rental financing, which starts at 20% down and often asks for more depending on the property and how many rentals you already own.

Lenders also apply portfolio limits. There is usually a ceiling on how many financed rental properties you can hold with one lender, and the down payment often has to come from your own resources rather than a gift. Our post on the investment property mortgage in Calgary breaks down the rental side in detail, and the investment property mortgage page covers how we structure those files.

When the A-Lender Path Does Not Fit

Everything above describes the A-lender route: banks, credit unions and monoline lenders, with debt ratios around 39% and 44% and income proven the traditional way. Self-employed buyers on that path are usually qualified on a two-year average of declared income from their notices of assessment, or through a business-for-self program with a reasonable gross-up.

If the file does not fit there, it is not over. Alternative (B) lenders can work below a 600 credit score depending on the whole picture, stretch debt ratios closer to 50% and 50%, and qualify a self-employed borrower off roughly twelve months of business bank statements without the most recent notice of assessment. That costs more and usually carries a lender fee, so it works best as a one to two year plan with a route back to an A lender. Private lenders are equity-focused, generally want 20% to 25% down or more with a written exit plan, and are the fallback when the property or the timeline will not wait.

One honest caveat: default insurance is not available on those paths. The 5% and 10% doors exist only on the insured A-lender side. If you are counting on a small down payment, the file has to be built to fit there from day one.

How Gold Lion Mortgages Can Help

Most declines on multi-unit deals are not about the buyer. They are about the file going to a lender who does not do that property type, or nobody checking the unit count against what the insurer will actually allow.

We have been placing files across the banks, credit unions, alternative lenders and private lenders since 2023, and we will tell you early if a building is going to be a problem instead of three days before your condition date.

Send us the listing and how you plan to use the place. We will come back with what the down payment looks like on that exact property, how much of the rent a lender will count, and what needs confirming before you write the offer. Call (587) 740-0048 or visit goldlionmortgages.com/apply.

Frequently Asked Questions

How much down payment do you need for a duplex in Canada?

If you are going to live in one of the two units, an insured mortgage can go up to 95% of the lending value, which means 5% down on the first $500,000 and 10% on the portion above. On a $700,000 duplex that works out to $45,000. The purchase price has to stay under $1.5 million to use the insured route. If you are buying the duplex purely as a rental, the minimum is 20% down.

Can you buy a fourplex with 5% down?

No. Three and four unit properties cap at 90% of the lending value even when you live in one of the units, so the minimum is 10% down. The 95% option applies only to one and two unit properties. A fourplex at $700,000 needs $70,000 down, against $45,000 for a duplex at the same price.

Do lenders count rental income from the other units?

Yes, though how much varies with the unit count. On an owner-occupied two-unit property, up to 100% of the gross rent from the other unit can be used, and some lenders remove property taxes and heat from your ratios as well. On an owner-occupied three or four unit property, the lender uses either up to 50% of gross rent or a net rental calculation. The rent has to be proven with signed leases or an appraiser's market rent opinion.

Is a duplex a residential or a commercial mortgage?

Two to four units is residential lending, so a duplex, triplex or fourplex is financed with a regular residential mortgage. At five units or more the deal becomes commercial, which means different lenders, a larger down payment and underwriting based on the building's income rather than only on yours.

What happens if one of the units is not legal?

The lender will usually treat the building as having one fewer unit, which lowers the rent that counts toward your income and can shrink the mortgage. Some lenders decline the file outright. Permits and municipal records need to match the listing, so confirm the unit count and the permits during your condition period rather than trusting the seller's description.

Published: August 26, 2026. Lender programs, insurer rules, municipal zoning and qualifying requirements all change. Contact Gold Lion Mortgages to confirm current requirements for your file, and confirm unit count, permits and permitted use with the municipality and your real estate lawyer.

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