Evaluating a multifamily investment property comes down to three things: verifying what the property actually earns, confirming what it costs to operate, and inspecting its physical condition. Get any one of those wrong and you can turn a promising deal into a money pit. Here’s how to work through each layer of the analysis so you can make a confident buy or walk decision.
Start With Net Operating Income
Net Operating Income, or NOI, is the single most important number in multifamily investing. It tells you how much money the property generates after you pay all operating costs but before you make any mortgage payments. The formula is simple: take gross potential income and subtract operating expenses.
Gross potential income means all the rent every unit would produce if the building were fully occupied and every tenant paid on time. Say you have a 10-unit building where each unit rents for $2,000 a month. That’s $240,000 a year in gross potential income. If annual operating expenses (property taxes, insurance, maintenance, management fees, utilities you cover, and vacancy losses) total $60,000, your NOI is $180,000.
The key word here is “actual.” Sellers and listing agents love to present pro forma numbers, which are projections of what the property could earn under ideal conditions. You want three years of actual financial statements, not pro formas. Request monthly rent rolls for the past 12 months so you can see which units are occupied, what each tenant actually pays, and how often rents have changed. Also ask for accounts receivable aging reports, which show you how much rent is overdue and how long it’s been outstanding. A building with $240,000 in gross potential income looks very different if $30,000 of that is chronically uncollected.
Use Cap Rate to Gauge Value
Once you have a reliable NOI, you can use the capitalization rate (cap rate) to estimate whether the asking price makes sense. Cap rate is NOI divided by the property’s purchase price, expressed as a percentage. A property with a $100,000 NOI selling for $2 million has a 5% cap rate.
You can also flip the formula to see what a property should be worth. Divide the NOI by the prevailing market cap rate for similar buildings in the area. If comparable multifamily properties are trading at a 5% cap rate and your target property produces $100,000 in NOI, its estimated market value is $2 million ($100,000 / 0.05).
Cap rates vary by location, property class, and market conditions. A newer building in a strong rental market might trade at a 4% cap rate, while an older property in a secondary market might need to offer 7% or 8% to attract buyers. The lower the cap rate, the more you’re paying per dollar of income, which generally reflects lower perceived risk. Compare the cap rate on your target property to recent sales of similar buildings nearby. If the seller is pricing at a cap rate well below the local norm, you’re overpaying unless there’s a clear reason the property commands a premium.
Calculate Cash-on-Cash Return
Cap rate ignores financing. Cash-on-cash return does not. This metric tells you what percentage return you’re earning on the actual cash you invested, including your down payment, closing costs, and any immediate renovations. The formula: divide your annual pre-tax cash flow (NOI minus annual mortgage payments) by the total cash you put in.
Suppose you buy a property for $2 million, put $500,000 down, and your annual mortgage payments total $100,000. If NOI is $180,000, your annual cash flow is $80,000. Divide that by your $500,000 investment and you get a 16% cash-on-cash return. That number lets you compare this deal against other investment options on an apples-to-apples basis, since it accounts for the cost of borrowing.
Multifamily loan rates currently sit in the range of roughly 5.6% to 7.8% depending on the loan structure and term length. Those rates directly affect your cash-on-cash return, so run multiple scenarios. Model what happens to your return if rates adjust upward on a variable-rate loan, or if you need to refinance in five years at a higher rate.
Stress-Test the Operating Expenses
Operating expenses on multifamily properties have averaged around 45% of gross income in recent years, a figure that has been relatively stable. That’s a useful benchmark, but it’s only a starting point. If the seller’s financials show expenses at 30% of income, something is probably missing or deferred.
Break the expenses into categories and verify each one independently. Property taxes are public record; pull the current assessment yourself rather than trusting the seller’s number. Insurance premiums have risen sharply in many markets, so get your own quote rather than relying on the seller’s existing policy cost. Ask for the capital expenditure history, which shows what the owner has spent on major repairs and replacements over the past several years. A building with suspiciously low maintenance costs may just have an owner who has been deferring work you’ll need to fund.
Management fees typically run 6% to 10% of collected rent for third-party management. Even if you plan to manage the property yourself, include a management fee in your analysis. At some point you may want to step back from day-to-day operations, and your numbers should still work when that happens.
Review Every Lease
The rent roll tells you what tenants are paying. The actual lease documents tell you what they’re entitled to. Review every lease for unusual clauses, below-market rents, long-term fixed rates, or problematic terms that could limit your ability to operate. A tenant with three years left on a lease at $800 a month in a $1,200 market creates a real gap in your income projections.
Pay attention to lease expiration dates. If most leases expire within the same few months, you face concentrated turnover risk. Look for any concessions the current owner granted, like free parking, waived pet fees, or rent discounts, that may not appear on the rent roll but reduce effective income.
Inspect the Physical Property
A professional inspection is non-negotiable, but you should also understand what the major cost drivers are so you can ask the right questions. Focus on the systems that are expensive to replace:
- Roof: Get its age, condition, and estimated remaining useful life. A roof replacement on a multifamily building can easily cost six figures.
- HVAC systems: Check the age of each unit’s heating and cooling equipment, the condition of shared systems, and whether maintenance records exist. Replacing HVAC across an entire building is one of the largest capital expenses you’ll face.
- Plumbing and electrical: Older buildings may have galvanized steel pipes or outdated wiring that needs full replacement, not just repair.
- Foundation and structure: Cracks, water intrusion, or settling can signal problems that cost tens of thousands to address, or indicate damage that can’t be fully corrected.
- Common areas and amenities: Lobbies, hallways, laundry rooms, parking lots, and landscaping all need ongoing maintenance budgets.
Get repair estimates for anything the inspection flags and subtract those costs from your investment analysis. A $50,000 roof repair within the first year changes your cash-on-cash return significantly.
Evaluate the Market and Location
The building’s numbers only matter if tenants want to live there. Research local vacancy rates for comparable properties. High vacancy in the area suggests either oversupply or weak demand, both of which threaten your income. Look at population trends, job growth, and whether major employers in the area are expanding or contracting.
Drive the neighborhood at different times of day. Check proximity to public transit, grocery stores, schools, and employment centers. Talk to local property managers about what renters in the area expect and what competing buildings charge. Online listings for nearby properties give you a real-time view of the rental market, including how long units sit vacant before leasing.
Run the Numbers Together
No single metric tells the full story. A property can have a great cap rate but need $200,000 in deferred maintenance. It can show strong NOI on paper but rely on above-market rents that will drop when leases turn over. The evaluation process works when you layer every piece together: verified income, realistic expenses, physical condition costs, financing terms, and market fundamentals.
Build a simple spreadsheet that models your projected returns over a five-year and ten-year hold period. Include rent growth assumptions (conservative ones), expected capital expenditures, and potential vacancy increases. If the deal still produces the return you need under pessimistic assumptions, it’s worth pursuing. If it only works when everything goes right, the margin of safety is too thin.