What Net operating income (NOI) means
NOI measures the income produced by the real estate itself. Keeping mortgage payments out of NOI lets two investors compare the same property even when they use different financing.
Include recurring property-level expenses such as taxes, insurance, repairs, management, owner-paid utilities, and association fees.
Exclude principal, interest, depreciation, income taxes, and capital improvements. Keep replacement reserves visible as a separate underwriting assumption.
NOI example
- Scheduled annual rent: $28,800
- Vacancy allowance: $1,440
- Operating expenses: $9,600
Result: $28,800 - $1,440 - $9,600 = $17,760 annual NOI.
When investors use it
- Comparing unlevered operating performance
- Calculating cap rate
- Testing DSCR and loan sizing
- Estimating value from an income approach
Common mistakes
- Subtracting the mortgage inside NOI
- Using current taxes when a sale will trigger reassessment
- Ignoring vacancy because the property is occupied today
- Treating a one-time renovation as a recurring operating expense
Frequently asked questions
Is mortgage payment included in NOI?
No. Debt service is excluded because NOI is designed to measure property operations before financing.
Is capital expenditure included in NOI?
Major capital improvements are normally tracked below NOI. Many investors still include a separate replacement-reserve assumption when judging sustainable cash flow.
Can NOI be negative?
Yes. If vacancy and operating expenses exceed operating income, NOI is negative and the property cannot support debt from operations.
This guide is educational and does not provide investment, lending, tax, legal, or appraisal advice. Verify inputs and requirements for the specific property, lender, and jurisdiction.
Put the metric inside a complete deal.
PropLurk keeps acquisition inputs, financing, expenses, returns, and the decision record together.