Last updated: November 5, 2026
Multifamily property with five or more units is generally considered commercial real estate, especially for lending, where it is financed with commercial or agency multifamily loans. Properties with two to four units are usually treated as residential and can use residential mortgages. Zoning, tax, and insurance classifications may follow different rules by location.
In US mortgage lending, residential loan programs typically cover one to four unit properties. Once a building has five or more units, it moves into commercial or multifamily lending, where loans are underwritten on the property's income rather than mainly on the borrower's personal income. That lending convention is the main reason five units is widely cited as the line.
A duplex, triplex, or fourplex can often be financed with conventional, FHA, VA, or DSCR loans designed for residential property. A five-unit or larger building usually uses bank commercial loans, agency multifamily programs, CMBS, or bridge loans. Commercial multifamily underwriting relies on NOI, DSCR, and LTV, and loans often have balloon maturities.
Zoning depends on the local code. Many cities place apartment buildings in residential zoning districts even though they are commercial for lending. Mixed-use buildings with retail on the ground floor may sit in commercial or mixed-use districts. Check the local zoning map and code for a specific property.
Property tax classification varies by state and county. Some jurisdictions treat larger apartment buildings differently from small rentals. Insurance carriers often write commercial policies for larger multifamily properties. A local tax professional and insurance broker can confirm how a particular building is treated.
Many investors start with two to four unit properties, which offer residential financing with rental income, then move into five-plus unit buildings as they gain experience and capital. The jump brings new financing tools and a more business-like approach to operations.
A building with apartments above ground-floor shops is usually treated as commercial for lending, even if it has fewer than five residential units, because of the commercial space. Student housing, senior housing, and manufactured housing communities have their own specialized lending programs. When a property does not fit neatly in one bucket, lenders will tell you which program applies.
Small residential properties are usually appraised mainly by comparing recent sales of similar homes and small rentals. Larger apartment buildings are valued mostly by their income, using NOI and market cap rates. That means improving operations, raising rents to market, or cutting waste can directly lift the value of a five-plus unit building in a way that is less direct for a duplex.
Is a fourplex commercial? For most lending purposes, no. It is typically residential.
Are apartment REITs commercial real estate? Yes, institutional multifamily is considered a commercial real estate sector.
Read next: briefcase.email/guides/how-do-commercial-real-estate-loans-work and briefcase.email/guides/what-is-cap-rate-in-commercial-real-estate.
Educational note: This page is general information, not investment, lending, tax, or legal advice. Briefcase is a media and marketing company, not a lender, broker, or advisor. Confirm terms and figures with qualified professionals before making decisions.
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