Commercial property evaluation starts with the income a building can sustain, the capital required to maintain it, and the debt structure used to own it. Four measures appear in many first reviews: net operating income, capitalization rate, debt-service coverage ratio, and cash-on-cash return. Each answers a different question. None should be used alone.

Use the calculations as a common language for investigation. Confirm leases, expenses, capital needs, and financing terms before trusting a polished model. Property type and local market conditions also matter. Research and professional groups such as NAIOP provide context across commercial real estate sectors, but the underwriting must still reflect the specific building.

Step one: calculate credible NOI

Net operating income, or NOI, is property revenue minus normal operating expenses before interest, income taxes, depreciation, and amortization. Revenue can include base rent, expense reimbursements, parking, storage, and other recurring property income. Vacancy and credit loss should reduce potential revenue. Operating expenses may include property taxes, insurance, utilities paid by ownership, repairs, management, landscaping, security, and routine administration.

Debt payments are excluded because NOI measures the property before financing. Large capital expenditures are generally analyzed separately because replacing a roof or mechanical system is not an ordinary annual operating expense. That accounting convention does not make capital needs disappear. A serious evaluation includes a reserve or separate capital plan.

Begin with trailing actual results, then normalize them. Remove one-time items only with a clear reason. Adjust below-market or above-market contracts carefully. Check whether taxes will reset after a sale. Review utility and insurance trends. Compare management fees with a market arrangement even if the current owner self-manages. The goal is not the highest possible NOI. It is a repeatable estimate a new owner can defend.

Step two: understand cap rate

The capitalization rate is NOI divided by property value or purchase price. If a building produces 500,000 dollars of annual NOI and costs 10 million dollars, the going-in cap rate is 5 percent. The measure allows a quick comparison of unlevered income yield, but it says little about future growth, capital costs, debt, or total return.

Lower cap rates often accompany properties viewed as safer or capable of stronger growth, while higher cap rates may reflect risk, weak demand, short leases, physical problems, or limited buyers. This is context, not a universal rule. JPMorgan’s explanation of commercial real estate cap rates is a useful starting reference for the relationship among NOI, value, and market conditions.

Use both a going-in cap rate and an exit assumption. The exit rate estimates the yield a future buyer may require when the property is sold. A model that assumes the exit rate will be lower than the purchase rate needs strong support. Test higher exit rates, slower rent growth, and longer vacancy. Small changes can have large effects on projected value.

Step three: test DSCR

Debt-service coverage ratio, or DSCR, is NOI divided by annual debt service. If NOI is 500,000 dollars and annual principal and interest payments total 400,000 dollars, DSCR is 1.25. That means current NOI covers scheduled debt service 1.25 times. A ratio below 1 indicates that property income does not cover the payment.

Lenders may require a minimum ratio that varies by property, borrower, and market. Underwriters should calculate DSCR using the lender’s definitions, not assumptions carried over from another deal. Check whether reserves, interest-only periods, amortization, and future rate changes alter the calculation.

Stress DSCR against realistic downside cases. What happens if a major tenant leaves, renewal rent falls, taxes rise, or repairs interrupt occupancy? A property with acceptable coverage today may face a difficult refinance if rates or lender standards change. The ratio is most useful as a durability test, not merely as a closing requirement.

Step four: measure cash-on-cash return

Cash-on-cash return is annual pre-tax cash flow divided by the cash invested. Cash flow here comes after operating expenses and debt service, with careful treatment of reserves and recurring capital needs. Cash invested includes the down payment plus closing costs and initial capital funded by the buyer.

Suppose a buyer invests 3 million dollars and expects 180,000 dollars of first-year pre-tax cash flow. The cash-on-cash return is 6 percent. The measure describes current cash yield on equity. It does not include appreciation, principal paydown, sale proceeds, or tax effects, so it should sit beside a full multi-year return analysis.

Heavy borrowing can raise projected cash-on-cash returns when performance is strong and destroy flexibility when performance weakens. Review the measure together with DSCR, loan maturity, rate structure, covenants, and capital reserves. Cash yield that depends on underfunded repairs is not a durable yield.

Move from ratios to the building

A model needs lease-level support. Read the leases and abstracts. Confirm rent steps, options, reimbursement clauses, termination rights, security deposits, and tenant obligations. Build a lease-expiration schedule. Compare in-place rents with supported market evidence and include realistic downtime, concessions, commissions, and tenant improvement costs.

Inspect the physical property with qualified professionals. Roofs, structure, mechanical systems, elevators, parking, environmental conditions, accessibility, and code issues can change the investment case. Industry organizations such as Urban Land Institute publish material on land use and property practice. Local specialists remain essential because buildings and regulations are specific.

Study supply and demand at the relevant scale. Citywide averages can hide a weak submarket or a strong block. Review competing space, construction, tenant movement, access, zoning, and local employment drivers. Data providers such as CoStar can support market research, but every material assumption should be checked against current, relevant evidence.

Build a decision table

Summarize the base case, downside case, and severe but plausible case. For each, show NOI, occupancy, required capital, DSCR, cash flow, exit value, and equity result. Identify the assumptions with the greatest effect. Record what evidence supports each and what remains uncertain.

Finally, write the reason to own the property in plain language. State how value will be preserved or created, what can go wrong, and which team has responsibility for execution. If the thesis only works under optimistic rent, low capital spending, and a favorable exit rate, the ratios are warning signs rather than confirmation.

NOI describes operating earnings. Cap rate relates those earnings to value. DSCR tests debt coverage. Cash-on-cash return measures current cash yield on invested equity. Used together, supported by leases, physical review, market evidence, and downside cases, they form a disciplined first view of a commercial property.