Reading the results
How to Read the Numbers on a Portland Duplex or Fourplex
Four figures decide most small multifamily deals. Cap rate tells you what the building earns relative to its price, independent of how you finance it. Cash flow before taxes is what actually reaches your account after the loan payment. Debt coverage ratio is the number your lender cares about most, and on investment property most want to see 1.20 or better, meaning the property earns twenty percent more than the mortgage costs. Cash on cash measures the return on the money you actually put in, which is often very different from the cap rate once a loan is involved.
At current interest rates, a lot of Portland duplexes and triplexes will show negative cash flow at the asking price. That is not automatically a bad deal. The total return view adds the loan principal your tenants retire each month along with any appreciation, which frequently turns a property that loses two hundred dollars a month into one that builds meaningful equity every year. It is worth understanding both numbers before you decide.
Local rules
Three Oregon Rules That Change the Math
Rent increases are capped statewide
Oregon has limited annual rent increases since Senate Bill 608 passed in 2019. The cap is the lesser of ten percent or seven percent plus regional inflation, and for 2026 the maximum allowable increase is 9.5 percent. Landlords may raise rent only once in a twelve month period, no increase is allowed during a tenant's first year, and buildings under fifteen years old are exempt. Inside Portland city limits, an increase of ten percent or more can trigger relocation assistance obligations, which in practice puts a lower ceiling on what most owners actually do. When a tenant moves out you can reset to market rent for the next one, which is why unit turnover matters so much on an older building.
Property taxes do not reset when you buy
This one surprises buyers coming from California. Under Oregon's Measure 50, a property's assessed value does not jump to your purchase price when it sells. You inherit the seller's assessed value, which continues growing at three percent a year. On a building someone has owned for twenty years, that assessed value can sit far below market value, and your tax bill will be lower than you would guess from the price. Pull the actual figure from the county rather than estimating from a percentage of what you paid.
Who pays the utilities changes everything
Older Portland small multifamily buildings are frequently on a single water meter, which leaves the owner paying water, sewer, and garbage for every unit. That can run two to four thousand dollars a year on a duplex, and it comes straight out of net operating income. Billing a share back to tenants is common, and the calculator has separate fields for water and garbage chargebacks so you can see the net cost rather than guessing.
For veterans
Buying a Duplex, Triplex, or Fourplex With a VA Loan
A VA loan can be used on a property of up to four units with no down payment, as long as you occupy one of them as your primary residence. That is one of the strongest wealth building tools available to a veteran in this market, and it is why this calculator includes a house hack view that most investment calculators do not. It removes your unit from the rent roll, applies VA terms including the funding fee, and shows what the building would cost you out of pocket each month compared with the rent you pay now. On a well priced fourplex, that number is often lower than renting.
Rental income from the other units can frequently be counted toward qualifying, though the rules vary by lender and by whether you have landlord experience. Veterans with a service connected disability rating are exempt from the funding fee entirely, which the calculator accounts for.
Not sure whether you qualify or how much of the rent a lender will count? That conversation is worth having before you start looking, and it costs nothing.
Common questions
Questions Buyers Ask Me Most
What is a good cap rate for a Portland duplex?
Portland small multifamily has generally traded in the four to six percent range, which is low compared with much of the country. Investors accept it because of long term appreciation and rent growth rather than immediate income. A cap rate well above that range in this market usually signals deferred maintenance, a difficult location, or rents already at the top of what the property can support.
How much do I need down on a duplex in Portland?
Conventional investment financing on two to four units typically requires twenty to twenty five percent down. If you will live in one unit, an FHA loan can go as low as 3.5 percent, and a VA loan can go to zero for eligible veterans. Occupying a unit is by far the cheapest way into this asset class.
Does this calculator save or share my information?
No. Everything you type stays in your browser and nothing is stored or transmitted. If you choose to send the analysis using the button at the bottom, it opens your own email program with the figures already filled in, and you decide whether to send it.
Can I use this for a five unit building?
It is built for two to four units, which is where residential financing applies. Five units and above is commercial lending, with different terms, different underwriting, and usually a larger down payment. Reach out and I can walk you through how that math differs.
Where I Work
I help buyers and sellers with small multifamily across the Portland metro and Southwest Washington, including North and Northeast Portland, Southeast Portland, Beaverton, Gresham, Milwaukie, Oregon City, and Vancouver. Licensed in Oregon and Washington. Call 503.997.4169 or email troy@nwrealtysource.com.
