Net Operating Income Calculator
Enter your gross rental income, other income sources, vacancy rate, and operating expenses to calculate Net Operating Income. NOI is the most fundamental metric in real estate investing — it measures a property's income-generating ability independent of financing.
Results are estimates for informational purposes only. Not financial advice. Full disclaimer.
What is Net Operating Income?
Net Operating Income (NOI) is the total income a property generates minus all operating expenses, before mortgage payments and income taxes. It is the single most important number in commercial real estate valuation because it represents the property's true earning power — independent of how it is financed or who owns it. NOI is the numerator in the cap rate formula (Cap Rate = NOI ÷ Property Value), which means it directly determines property value in the eyes of commercial lenders and institutional investors. A property with higher NOI is worth more. Increasing NOI by $1,000 in a 5% cap rate market increases the property's value by $20,000 ($1,000 ÷ 0.05). The calculation starts with Gross Potential Income — the total rent if every unit were occupied at market rate for the full year, plus any other income (laundry, parking, storage, application fees). Then a vacancy and credit loss allowance is subtracted to arrive at Effective Gross Income — the realistic amount you expect to collect. Finally, operating expenses are subtracted to arrive at NOI. Operating expenses include everything required to run the property: property taxes, insurance, maintenance and repairs, property management fees, utilities paid by the landlord, landscaping, pest control, legal fees, accounting, and reserves for replacements. Operating expenses explicitly exclude mortgage payments (debt service), capital expenditures (major replacements like roofs), depreciation, and income taxes — these are financing and accounting items, not operating costs. The Operating Expense Ratio (OER) shows what percentage of effective income goes to expenses. For well-managed residential properties, the OER typically ranges from 35% to 50%. Ratios above 50% suggest the property may have excessive expenses or below-market rents. Ratios below 30% may indicate that some expenses are being underestimated.
How to Calculate
- Enter the gross annual rental income (monthly rent × 12 × number of units, at full occupancy)
- Add any other income sources (laundry, parking, storage, pet fees, application fees)
- Set the vacancy rate (5% for stable markets, 8-10% for higher turnover)
- Enter total annual operating expenses (taxes, insurance, maintenance, management, utilities, reserves)
- Review NOI and the operating expense ratio
Formula
Gross Potential Income = Gross Rental Income + Other Income Effective Gross Income = Gross Potential Income × (1 − Vacancy Rate ÷ 100) Net Operating Income (NOI) = Effective Gross Income − Annual Operating Expenses Operating Expense Ratio = Annual Operating Expenses ÷ Effective Gross Income × 100 Remember: NOI does NOT subtract mortgage payments, capital expenditures, or depreciation. These are excluded intentionally so that NOI measures the property's performance, not the owner's financing or tax situation.
Example Calculation
For a property with $24,000 gross annual rental income, $0 other income, 5% vacancy, and $8,000 operating expenses: Gross Potential Income = $24,000 + $0 = $24,000 Effective Gross Income = $24,000 × (1 − 0.05) = $22,800 NOI = $22,800 − $8,000 = $14,800 Operating Expense Ratio = $8,000 ÷ $22,800 × 100 = 35.09% This $14,800 NOI with a 35% expense ratio indicates a well-managed property. At a 5% cap rate, this property would be valued at $296,000 ($14,800 ÷ 0.05).
Frequently Asked Questions
Why does NOI exclude mortgage payments?
NOI measures the property's intrinsic earning power, not your personal financial situation. Two investors buying the same property — one with cash, one with a 80% mortgage — will see the same NOI but very different cash flow. By excluding financing, NOI provides an apples-to-apples comparison metric that lenders, appraisers, and buyers all rely on.
What is a good operating expense ratio?
For residential rental properties, a healthy OER is 35-50%. Below 35% may indicate underestimated expenses (are you budgeting for maintenance reserves and vacancy?). Above 50% suggests high costs relative to income — either expenses are too high or rents are too low. Commercial properties with NNN leases can have much lower OERs because tenants pay most operating costs.
How is NOI used to value a property?
Property Value = NOI ÷ Cap Rate. This is the income approach to valuation, used by appraisers and commercial lenders. If a property generates $14,800 NOI and the market cap rate is 5%, the property is worth approximately $296,000. Increasing NOI through higher rents or lower expenses directly increases the property's market value.
What counts as 'other income' for a rental property?
Other income includes any revenue beyond base rent: coin-operated laundry ($50-200/unit/year), parking fees, storage unit rentals, pet fees or pet rent, application fees, late fees, early termination fees, and billboard or antenna leases. For single-family rentals, other income is often zero. For multifamily, it can be 3-8% of gross rental income.
Should I include a reserve for capital expenditures in operating expenses?
Industry practice varies. For NOI calculation used in property valuation, capital reserves (replacement reserves) are sometimes included and sometimes excluded. Lenders often add a reserve of $200-300 per unit per year. For your own analysis, always include a CapEx reserve — the 50% rule already approximates this, but budgeting $100-250/month per unit for a dedicated CapEx fund is prudent.
How do I increase NOI on a rental property?
There are two levers: increase income or decrease expenses. Income strategies: raise rents to market rate, add income streams (laundry, parking, storage), reduce vacancy through better marketing or tenant retention. Expense strategies: appeal property tax assessments, shop insurance annually, perform preventive maintenance (cheaper than emergency repairs), and negotiate property management fees. Each $1 of NOI increase amplifies property value through the cap rate multiplier.