Net Operating Income (NOI): Definition, Formula & Underwriting Guide
Net Operating Income (NOI) is the fundamental measure of a commercial property’s profitability, calculated as total operating revenue minus operating expenses, before debt service and taxes.
Ready to Calculate NOI for Your Deal?
Model gross rent, vacancy allowances, expense categories, and replacement reserves with our free interactive tool.
What is NOI (Net Operating Income)?
Net Operating Income (NOI) reflects the true operational earning power of a commercial real estate property. It includes all revenue generated on-site (gross rental income, utility reimbursements, storage fees, parking fees, laundry income) and subtracts all normal, routine property operating expenses (property taxes, insurance, property management fees, utilities, routine maintenance, repairs, and landscaping). Crucially, NOI is calculated before deducting debt service (mortgage principal and interest payments), capital expenditures (CapEx), depreciation, and income taxes. This makes NOI an unleveraged, property-level metric that allows investors and appraisers to compare the fundamental earning power of assets regardless of individual owner financing structures.
Why This Metric Matters in CRE Underwriting
NOI serves as the critical numerator in calculating Capitalization Rates (Cap Rate = NOI / Price) and the critical numerator in determining Debt Service Coverage Ratio (DSCR = NOI / Annual Debt Service). Commercial lenders and appraisers base asset valuations directly on audited historical trailing 12-month (T12) NOI.
NOI Formula & Equation
NOI = Effective Gross Income (EGI) - Total Operating Expenses (OpEx)Worked Commercial Example
A 20-unit apartment building produces $300,000 in Gross Potential Rent with a 5% vacancy loss ($15,000) and $10,000 in parking income, giving an EGI of $295,000. Annual property taxes are $42,000, insurance is $14,000, management is $20,000, and repairs/utilities total $39,000 (total OpEx = $115,000).
Analysis: The property produces $180,000 in annual net operating cash before paying any mortgage debt or investor distributions.
NOI Industry Rules of Thumb & Benchmarks
- Operating Expense Ratios (OpEx / EGI) typically range between 40% to 52% for multifamily.
- Institutional NNN retail assets often have OpEx ratios under 10% due to expense pass-throughs.
- High-rise urban office buildings often see OpEx ratios exceeding 55%.
Frequently Asked Questions (FAQs)
Does NOI include mortgage payments?
No. Mortgage principal and interest payments are classified as Debt Service and are deducted below NOI to arrive at Cash Flow Before Taxes (CFBT).
Is CapEx included in operating expenses for NOI?
No. Major capital improvements (like a new roof or HVAC replacement) are capitalized and depreciated over time, rather than expensed directly in operational NOI.
What is the difference between GPI and EGI in NOI calculations?
Gross Potential Income (GPI) is theoretical 100% full-capacity rent. Effective Gross Income (EGI) adjusts for real-world tenant vacancy and bad debt, plus adds ancillary fee revenues.