Home · Resource Center · NOI Explained
NOI is rental revenue minus operating expenses, before debt service. Cap rate divides that NOI by price. DSCR divides it by annual debt service.
By RentalAnalytics Editorial Team · Published September 3, 2026
Net operating income is the profit a rental earns from running the property, before you pay the bank or the tax authority. Investopedia states the identity as real estate revenue minus operating expenses, and notes that NOI is a before-income-tax figure that excludes principal and interest, capital expenditures, depreciation, and amortization.[1]
That exclusion is the feature. Two buyers can pay the same price for the same building, one with cash and one with a loan, and still compute the same NOI. The loan changes cash flow and DSCR. It does not change what the property itself earns from tenants after the cost of keeping the lights on.
Work top to bottom. Do not jump from asking rent to "profit."
Here is a walkthrough that matches the inputs used in our cash flow guide. A unit rents for $2,400 a month. A 7% vacancy allowance takes annual scheduled rent of $28,800 down to $26,784 of effective gross income. Operating costs are $4,200 property tax, $1,600 insurance, $1,800 maintenance ($150 a month), and an 8% management fee on effective gross income ($2,143). Expenses total $9,743. NOI is $26,784 minus $9,743, or $17,041 a year, about $1,420 a month. That NOI does not move if you change the down payment.
The rent input should be a market estimate or an in-place lease, not Fair Market Rent labeled as market. On this site, estimated market rent is a HUD FY2026 50th-percentile plus Census ACS blend. HUD FMR stays the 40th-percentile / voucher figure. See methodology and the rent estimator if you need the ZIP-level path.
Estimated change in net operating income comes from the operating lines, not from the loan. In the worked rental on this page, scheduled rent is $2,400 a month, or $28,800 a year. A 7% vacancy allowance reduces that to $26,784 of effective gross income. Operating expenses are $4,200 of property tax, $1,600 of insurance, $1,800 of maintenance, and an 8% management fee on effective gross income ($2,143). Expenses total $9,743. NOI is $26,784 minus $9,743, which is $17,041 a year, about $1,420 a month.
Move scheduled rent, vacancy, other recurring property income, or an operating expense, and NOI moves with that line. Move only the mortgage, and NOI stays $17,041. The loan shows up in cash flow and in DSCR. Cap rate uses this NOI and the price: $17,041 on a $320,000 price is a 5.3% cap rate, and the same NOI on a $250,000 price is a 6.8% cap rate. DSCR divides the same NOI by annual debt service. Against $18,500 of debt service, DSCR is 0.92. Against $13,600 of debt service, DSCR is 1.25.
Vacancy is subtracted before expenses. The operating expenses in this walkthrough are taxes, insurance, maintenance, and management. Loan principal and interest, capital expenditures, depreciation, amortization, and income tax stay out of NOI. Leave vacancy or management out and the estimated NOI comes out higher than $17,041.
See this NOI on your numbers
The walkthrough NOI is $17,041 before any loan payment. Open the cash flow analyzer to compute NOI, then cash flow after debt. Open the cap rate calculator when you want NOI divided by price.
Investopedia lists the main omissions: loan principal and interest, capital expenditures, depreciation, and amortization.[1] Each one is left out for a different reason.
The most common seller-statement error is the reverse: leaving vacancy, management, or a maintenance reserve out of expenses so NOI looks institutional. National Apartment Association coverage of elevated operating costs is a reminder that opex is not a rounding error. Stabilized residential rentals often land in a mid-30s to mid-40s percent-of-income band once the full stack is counted.[3] If a broker NOI implies a 20% expense ratio on a garden-variety single-family rental, rebuild the stack.
Cap rate is NOI divided by purchase price (or value). A $17,041 NOI on a $320,000 price is a 5.3% cap rate. The same NOI on a $250,000 price is a 6.8% cap rate. Price is the lever. That is why a 1% screen and a cap-rate screen can disagree: the 1% rule uses gross rent, while cap rate uses rent after vacancy and expenses.
Cap rate is the unlevered yield. It answers whether the property is worth the price, independent of your loan. The longer comparison of that yield versus cash-on-cash return (NOI minus debt service, divided by cash invested) is already on the site: Cap rate vs. cash-on-cash. Use the cap rate calculator when you want the identity next to a metro-tier band.
If you sell the building and roll the proceeds into another rental, NOI is still the income that has to carry the next loan. The partial 1031 exchange explainer separates boot from deferred gain, and the 1031 exchange calculator runs the replacement value test beside the 45-day and 180-day dates.
Debt service coverage ratio is NOI divided by annual principal and interest. A $17,041 NOI against $18,500 of annual debt service is a 0.92 DSCR: the property does not cover its own loan from operations. The same NOI against $13,600 of debt service is a 1.25 DSCR, the band many DSCR programs treat as the start of cleaner pricing.
Because the numerator is NOI, every expense you forgot to include inflates DSCR the same way it inflates cap rate. The full lender-threshold walkthrough is in DSCR explained for rental investors. Rate movement changes only the denominator. That is why a deal that cleared 1.25 two years ago can fail the same program today with unchanged rent.
Compute it once, then reuse it. The cash flow analyzer prints NOI on the P&L, then subtracts debt service to get cash flow. That is the correct order: operations first, financing second. The 1% rule can decide whether a listing is worth that much work. NOI is the number you keep after the listing survives.
This is an educational walkthrough of a definition and two identities. It is not advice to buy, finance, or value a specific property. If a seller's NOI and your NOI disagree, the difference is almost always vacancy, management, or CapEx, not a rounding error in the formula.
A legal limit on rent growth changes the income side of NOI even when the expense lines stay put. See Rent Control 101: What It Does to Your Cash Flow.
NOI is property revenue minus operating expenses, before debt service, capital expenditures, depreciation, and income tax. It is what the building earns from operations. It is not what a particular loan leaves in the owner's account.
NOI changes when rent, vacancy, other recurring property income, or operating expenses change. In the walkthrough, scheduled rent of $28,800 minus a 7% vacancy allowance is $26,784 of effective gross income, expenses are $9,743, and NOI is $17,041. Changing the loan does not change that NOI.
Start with scheduled rent, subtract vacancy and credit loss, add other recurring property income, then subtract operating expenses such as taxes, insurance, maintenance, management, and owner-paid utilities. Do not subtract the mortgage.
No. Principal and interest are financing. Two buyers of the same building, one all-cash and one leveraged, compute the same NOI. Subtract debt service after NOI to get pretax cash flow.
Cap rate is NOI divided by purchase price. DSCR is NOI divided by annual debt service. The $17,041 walkthrough is a 5.3% cap rate on a $320,000 price and a 6.8% cap rate on a $250,000 price. Against $18,500 of debt service, DSCR is 0.92. Against $13,600, DSCR is 1.25.
More on RentalAnalytics → all articles · all tools · city reports