Real Estate Glossary
What is NOI (Net Operating Income)? Definition, Formula & Examples
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Definition
Net Operating Income (NOI) is the annual income a property generates after all operating expenses are deducted, but before mortgage payments, income taxes, and depreciation. It is the foundational number for nearly every real estate investment analysis, used to calculate cap rate, DSCR, and property value. NOI represents what the property itself earns, independent of how it is financed.
The NOI (Net Operating Income) Formula
Variables explained:
Gross Rental Income is the total rent if all units were occupied 100% of the year. Vacancy Loss is your estimated vacancy allowance (e.g., 5% = 18 days/year empty). Operating Expenses include property taxes, insurance, property management fees, maintenance, repairs, HOA dues, and utilities paid by the owner — but NOT the mortgage payment.
NOI (Net Operating Income) Example with Real Numbers
A single-family rental collects $2,200/month in rent ($26,400/year). You estimate 5% vacancy ($1,320 loss), leaving effective gross income of $25,080. Operating expenses: property tax $3,600, insurance $1,200, management (10%) $2,508, maintenance $2,000, miscellaneous $500 = $9,808 total. NOI = $25,080 − $9,808 = $15,272/year.
Why NOI (Net Operating Income) Matters for Investors
NOI is the building block for every key metric. Divide it by the purchase price and you get cap rate. Divide it by annual debt service and you get DSCR. Commercial appraisers literally derive a property's value by dividing its NOI by the prevailing market cap rate. Getting NOI wrong distorts everything downstream.
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Frequently Asked Questions
Does NOI include the mortgage payment?
No. The mortgage (principal and interest) is a financing cost, not an operating expense. NOI measures property performance before financing so that different investors with different loan terms can compare properties fairly.
Does NOI include depreciation?
No. Depreciation is a non-cash tax accounting entry. NOI is a cash-based measure of actual property income before tax effects.
What is the difference between NOI and cash flow?
Cash flow (before tax) = NOI minus annual debt service (mortgage P&I). NOI is pre-financing; cash flow is post-financing. A property can have strong NOI but negative cash flow if heavily leveraged.
How do you increase NOI?
Increase rents, reduce vacancy, add ancillary income (laundry, parking, storage), or cut operating expenses through energy efficiency, renegotiating insurance, or self-managing the property.
Related Terms
Cap Rate
Cap rate (capitalization rate) is the ratio of a property's annual net operating income (N…
DSCR (Debt Service Coverage Ratio)
The Debt Service Coverage Ratio (DSCR) measures how many times a property's net operating …
NOI Formula
The NOI formula calculates a property's annual net operating income by subtracting vacancy…
Operating Expense Ratio (OER)
The Operating Expense Ratio (OER) is the percentage of a property's gross operating income…
Cash Flow in Real Estate
Cash flow in real estate is the net money remaining after all property income has been col…