Buying a Duplex, Triplex or Fourplex to Live In: Conventional Rules

Buying a duplex, triplex or fourplex and living in one unit can combine a home purchase with rental income. The financing still has to work as an owner occupied mortgage, with eligible units, documented rents and enough cash left after closing.

Don't start by subtracting advertised rent from the mortgage payment and assuming the difference is what the lender will underwrite. The qualifying calculation is different from the property's operating budget.

The basics

Live in one unit, rent the others. Conventional generally allows 5% down on two to four unit primary residences, with loan limits up to $1,601,750 for a fourplex in 2026. Reserves are typically required.

Rental income

Lenders usually count 75% of the rents to help you qualify. Unlike FHA, conventional doesn't use a self sufficiency test on three and four unit homes.

Running the numbers like an investor

Look at rent, vacancy, repairs, insurance, taxes and capital expenses like roofs and HVAC before you look at the loan. A good small multifamily works even if a unit sits empty for a couple of months. If it only works fully rented, keep looking.

Conventional vs FHA vs VA

FHA allows 3.5% down but uses the self sufficiency test on three and four units and keeps mortgage insurance for the life of the loan. VA allows no down payment with full entitlement and no monthly insurance. See FHA multifamily and VA multifamily. USDA doesn't allow multi unit properties.

Reserves, leases and the appraiser

Expect a reserve requirement on two to four unit purchases. For rental income, lenders use current leases when units are rented, or the appraiser's market rent estimate when they're not. If leases are below market, that's what counts, so check them before you offer.

What I learned living in my fourplex

Living on site taught me the landlord side fast. Screen tenants carefully, budget for turnover between tenants, and price insurance before you buy. Older Florida multifamily buildings can carry surprising insurance costs, and that changes the math on every deal.

After you move out

See turning your home into a rental.

Conventional has no rule against keeping it as a rental after you've lived there. Your next home can be financed separately, conventional or otherwise.

I bought my first fourplex in 2011. House hacking is still one of the best ways to start.

A fourplex that failed FHA's test

Ben's fourplex didn't pass FHA's self sufficiency test. With a 750 score and 5% down on a conventional loan, the test didn't apply, and 75% of the other units' rent helped him qualify.

Confirm the unit count and occupancy plan

A legal duplex is different from a single family home with an accessory unit or an unpermitted conversion. The appraisal, zoning and property records must support the correct classification. Five or more units also leave the ordinary one to four unit residential framework.

Tell the lender which unit you'll occupy and what the other units are actually used for. Owner occupied financing requires a genuine qualifying occupancy plan. It isn't a rate selection for a property you intend to operate entirely as a rental.

Legal unit count also affects loan limits, valuation and available products. Verify those details before relying on a listing description.

Five percent down can be possible under the right conventional path

Fannie Mae's current standard DU matrix permits up to 95% leverage for eligible two to four unit principal purchase transactions. That can allow 5% down when all conditions are met. It isn't the rule for every high balance loan, manually underwritten file or product combination.

Hypothetical example: a $600,000 duplex at 95% leverage has a $570,000 base loan and $30,000 down payment, assuming supported value and eligibility. Closing expenses and required reserves are additional.

Ask the lender to confirm the specific matrix, unit count, county loan limit and automated findings. A general statement that multifamily always requires 20% down can miss eligible options, while promising 5% on every building is equally misleading.

Rental income needs a current rule review

Under Fannie's current subject property rental guidance, the lender must document your current housing payment to use rental income. The purchase also needs appropriate appraiser rent support and applicable transferred lease documentation.

The calculation generally begins with 75% of supported gross rent and considers the property's PITIA and your management experience. Without at least 12 months of qualifying experience, positive adjusted income is restricted to offsetting the applicable housing obligation rather than creating unlimited additional income.

A buyer living rent free should flag that immediately. The planned new mortgage payment isn't automatically a substitute for the required current housing payment documentation.

Your unit doesn't create rent for qualification

Rent from the unit you'll occupy is generally not counted as rental income. The other units' supported rents are evaluated under the program. A seller's projection for short term rental revenue isn't automatically equivalent to eligible long term rent documentation.

If existing leases differ from appraiser supported market rent, the lender must resolve the discrepancy under the applicable guidance. Don't assume the larger number wins.

Other programs have different rental tests. FHA and VA should be evaluated under their own rules rather than by importing this conventional calculation.

Full housing expense stays in the principal residence ratio

Hypothetical conventional example: monthly employment income is $8,000. Eligible rent from the other unit is $2,000 gross, with $1,500 usable after the 75% factor, assuming the borrower and documents meet the required conditions. Proposed full PITIA is $4,000 and other debt is $600.

For the principal residence treatment, qualifying income is $9,500 and obligations are $4,600, for about 48.4% DTI. The $1,500 is below PITIA, so this illustration doesn't rely on positive surplus rent.

Subtracting rent from PITIA and dividing $3,100 by $8,000 would show 38.75%. That is a different calculation and would overstate the qualifying benefit under the stated treatment. Neither percentage is an approval promise.

Reserves can be the larger cash obstacle

Fannie's DU baseline includes six months of reserves for two to four unit primary transactions, with the actual file and additional requirements still to be reviewed. At $4,000 a month, six months equals $24,000 remaining after closing.

Combine the example's $30,000 down payment, hypothetical $15,000 of costs and $24,000 of reserves. That is $69,000 of eligible funds before other adjustments or an additional personal safety cushion. The amount wired at closing isn't the entire asset requirement.

Eligible noncash assets may support reserves under applicable rules. Conventional reserves explains the worksheet.

Gifts and affordable products require separate attention

Under Fannie's standard gift rule, a two to four unit principal residence above 80% leverage generally requires 5% from the buyer's own funds, with specific exceptions and different product provisions. Don't assume a parental gift can replace every dollar of a standard 5% contribution.

HomeReady and other eligible structures can have different conditions. Ask for a complete product comparison using the actual units and source plan, rather than applying a one unit 3% down headline.

Underwrite the ownership budget too

Set aside money for vacancy, repairs, turnover and utilities paid by the owner. The agency's rent factor and reserve requirement are underwriting measures, not a personalized operating forecast.

Before offering, get the unit classification, supported rents, qualifying income treatment, full payment and source and reserve plan reviewed together. That is how a promising house hack becomes a purchase that can close and remain manageable afterward.