Key takeaways
- Net operating income measures property income after operating expenses.
- A simple formula is NOI = Property Operating Revenue - Operating Expenses.
- A more detailed rental-property formula is NOI = Effective Gross Income - Operating Expenses.
- Rental income and other recurring property income may contribute to NOI.
- Property taxes, insurance, repairs, maintenance, management fees, HOA fees, and landlord-paid utilities are common operating expenses.
- Mortgage principal and interest are generally excluded from NOI because financing is separate from property operations.
- Depreciation and income taxes are generally excluded from NOI.
- Capital expenditures are generally not treated as normal operating expenses in the NOI calculation.
- NOI is not the same as cash flow, taxable income, or accounting net income.
- NOI is commonly used to calculate cap rate and compare rental properties.
On this page
- What Is Rental Property NOI?
- Rental Property NOI Formula
- NOI Calculation Flow
- Why NOI Matters for Landlords
- What Income Is Included in NOI?
- What Expenses Are Included in NOI?
- What Is Not Included in NOI?
- Rental Property NOI Example
- NOI vs. Cash Flow
- NOI vs. Net Income
- NOI vs. Gross Rental Income
- NOI and Cap Rate
- NOI Margin
- How to Improve Rental Property NOI
- Common NOI Calculation Mistakes
- Actual NOI vs. Projected NOI
- How PropioLedger Helps Track the Numbers Behind NOI
- Frequently Asked Questions
- Educational Disclaimer
What Is Rental Property NOI?
Net operating income, commonly abbreviated as NOI, measures the income generated by a rental property after subtracting the property’s operating expenses.
NOI is designed to measure the operating performance of the real estate itself. That distinction is important.
Two landlords could own identical properties with identical rents and expenses but finance them differently. One might have no mortgage while the other has a large loan. Their cash flow would be different because of debt payments, but the properties could have the same NOI.
That makes NOI particularly useful for comparing properties without allowing financing decisions to distort the comparison.
NOI can help landlords answer practical questions: how much income a property generates from operations, how expensive it is to operate, whether performance is improving or declining, how one rental compares with another, what cap rate the property produces, and how rent or expense changes may affect performance.
However, NOI is often confused with cash flow, taxable income, and accounting profit. Understanding what belongs in the calculation, and what does not, is essential.
Rental Property NOI Formula
A simple rental property NOI formula is NOI = Property Operating Revenue - Operating Expenses.
Property operating revenue is income generated through operation of the rental property. Operating expenses are recurring costs required to operate and maintain the property.
A more detailed rental-property calculation often uses NOI = Effective Gross Income - Operating Expenses.
In a simple annual example, a property with $48,000 of effective gross income and $18,000 of operating expenses has $30,000 of NOI.
In this simplified example, the rental property’s annual net operating income is $30,000.
Potential Gross Income vs. Effective Gross Income
A more detailed NOI calculation may begin with the income a property could generate at full occupancy and then adjust for vacancy or collection losses.
Potential gross income is the income the property could generate if all rentable space were occupied and all expected rent were collected.
Vacancy and credit loss represent estimated or actual income lost because of vacancies, nonpayment, concessions, or collection issues.
Other property income may include parking, laundry, pet-related income, storage, utility reimbursements, and other operating revenue.
The result is often referred to as effective gross income. Effective gross income minus operating expenses equals NOI.
NOI = Effective Gross Income - Operating Expenses
| NOI Calculation | Amount |
|---|---|
| Effective gross income | $48,000 |
| Operating expenses | ($18,000) |
| Net operating income | $30,000 |
NOI Calculation Flow
Many landlords find NOI easier to understand as a flow from possible income to actual operating performance.
Why NOI Matters for Landlords
NOI provides a standardized way to evaluate operating performance before financing and certain owner-specific costs.
Landlords can use NOI to compare rental properties, monitor performance over time, identify rising operating expenses, evaluate rent increases, measure vacancy impact, estimate cap rate, review potential acquisitions, understand whether operational changes are improving a property, and provide useful operating information for lenders, partners, or investors.
NOI does not tell a landlord how much cash is ultimately left in their bank account. Instead, it isolates the operating performance of the property before financing and certain other costs.
What Income Is Included in NOI?
Income used in NOI generally comes from operating the property. The goal is to capture income generated by normal property operations.
Whether a particular charge belongs in NOI depends on the nature of the income and the reporting method being used. Consistency matters when comparing properties or periods.
Refundable security deposits generally are not property operating revenue when received because the landlord may be required to return them.
| Income Category | Example |
|---|---|
| Base rent | Monthly rental payments |
| Parking income | Garage, carport, or parking-space charges |
| Laundry income | Coin, card, or app-based laundry revenue |
| Storage income | Storage unit or storage-space charges |
| Pet-related income | Recurring pet rent or other earned pet-related charges |
| Utility reimbursements | Amounts renters reimburse for landlord-paid utilities |
| Other property operating revenue | Other recurring income generated by the property |
What Expenses Are Included in NOI?
Operating expenses are the ordinary costs required to operate and maintain the rental property.
The exact categories included can vary by property type, reporting purpose, and accounting practice. Consistency is important when comparing NOI across properties or periods.
| Operating Expense | Example |
|---|---|
| Property taxes | Local real estate taxes |
| Property insurance | Landlord or property insurance |
| Repairs | Plumbing, electrical, appliance, or other repairs |
| Routine maintenance | Preventive and recurring maintenance |
| Property management | Management company or manager fees |
| HOA fees | Recurring association dues when applicable |
| Landlord-paid utilities | Water, electricity, gas, trash, internet, etc. |
| Landscaping | Lawn, tree, irrigation, or grounds maintenance |
| Pest control | Recurring pest-management services |
| Cleaning | Common-area or turnover-related operating cleaning when applicable |
| Accounting or administrative costs | Property-related operating administration when appropriate |
What Is Not Included in NOI?
NOI intentionally excludes several costs even though those costs may affect actual cash flow or accounting results.
Excluded from NOI does not mean the cost is unimportant. A landlord still needs to budget for mortgage payments, capital expenditures, taxes, and other cash requirements. They simply answer different financial questions.
Property taxes and income taxes are different for NOI purposes. Real estate property taxes are commonly treated as property operating expenses, while the owner’s federal, state, or other income taxes are generally excluded from NOI.
Capital Expenditures vs. Operating Expenses
One of the most common NOI mistakes is treating every property expenditure as an operating expense.
Routine repairs and maintenance are generally part of property operations. Examples may include repairing a leaking faucet, HVAC service, minor plumbing repair, routine landscaping, and pest control.
Major improvements or replacements that provide benefits over multiple years may instead be treated as capital expenditures. Examples may include replacing the roof, installing a new HVAC system, a major kitchen renovation, adding a room, or a significant structural improvement.
Some investment analyses also include a replacement-reserve assumption below NOI or as a separate adjustment even though the reserve itself is generally not treated as a standard NOI operating expense.
Classification depends on the facts, reporting purpose, accounting practices, and applicable tax rules. Landlords should consult qualified professionals when determining the proper treatment.
| Usually Excluded from NOI | Why |
|---|---|
| Mortgage principal | Financing activity rather than property operating expense |
| Mortgage interest | Financing cost rather than property operating expense |
| Owner income taxes | Owner-specific rather than property operating expense |
| Depreciation | Non-cash accounting expense |
| Capital expenditures | Long-term investment rather than ordinary recurring operating expense |
| Owner distributions | Movement of owner equity, not property operating expense |
| Property acquisition costs | Investment or acquisition activity rather than ongoing operations |
Rental Property NOI Example
Assume a fictional four-unit rental property has $72,000 of annual potential rental income. The landlord estimates $3,600 of vacancy and credit loss, plus $2,400 of parking income and $1,200 of laundry income.
$72,000 of potential rent minus $3,600 of vacancy and credit loss plus $3,600 of other property income equals $72,000 of effective gross income.
The property also has $30,000 of annual operating expenses, including property taxes, insurance, repairs and maintenance, property management, utilities, landscaping, pest control, and other operating expenses.
$72,000 of effective gross income minus $30,000 of operating expenses equals $42,000 of NOI.
The property’s NOI is $42,000. Mortgage payments have not been deducted because NOI measures property operations before financing.
| NOI Calculation | Amount |
|---|---|
| Potential rental income | $72,000 |
| Less vacancy & credit loss | ($3,600) |
| Other property income | $3,600 |
| Effective gross income | $72,000 |
| Operating expenses | ($30,000) |
| Net operating income | $42,000 |
NOI vs. Cash Flow
NOI and cash flow answer different questions. NOI asks how well the property itself performs operationally. Cash flow asks how much cash is left after the landlord’s actual cash inflows and outflows.
If a property produces $42,000 of NOI and annual mortgage payments are $27,000, a simplified before-tax cash flow calculation might begin with $42,000 minus $27,000, or $15,000.
This is only a simplified bridge from NOI to owner cash flow. Actual cash flow may also be affected by capital expenditures, reserves, financing costs, owner-level expenses, and other cash activity.
| NOI | Cash Flow |
|---|---|
| Measures property operating performance | Measures actual cash movement |
| Excludes mortgage payments | Includes debt payments when evaluating owner cash flow |
| Excludes capital expenditures | Capital expenditures reduce actual cash |
| Useful for comparing properties | Useful for evaluating owner liquidity |
| Used in cap rate | Used to understand cash remaining to the owner |
NOI vs. Net Income
NOI and accounting net income are sometimes confused, but they are not the same metric.
NOI measures property operations before financing, depreciation, taxes, and certain other items. Accounting net income may include additional expenses that NOI excludes.
NOI should not automatically be treated as taxable income or accounting net income.
| NOI | Accounting Net Income |
|---|---|
| Property operating metric | Accounting profitability metric |
| Before financing costs | May include interest expense |
| Before depreciation | May include depreciation |
| Before owner income taxes | Tax treatment depends on reporting context |
| Useful for property comparison | Useful for accounting and financial reporting |
NOI vs. Gross Rental Income
Gross rental income looks primarily at revenue. NOI accounts for the cost of operating the property.
Gross rental income generally focuses on rental revenue before operating expenses, while effective gross income may also reflect vacancy, credit loss, and other property income depending on the analysis.
For example, Property A may have $60,000 of gross income, $20,000 of operating expenses, and $40,000 of NOI. Property B may have $65,000 of gross income, $32,000 of operating expenses, and $33,000 of NOI.
Even though Property B collects more revenue, Property A produces more NOI. Revenue alone is not enough to evaluate property performance.
NOI and Cap Rate
NOI is commonly used to calculate capitalization rate, or cap rate.
The basic formula is Cap Rate = NOI / Property Value.
The value used should be appropriate to the analysis. Investors commonly use current market value when evaluating an existing property’s cap rate, while purchase price may be used when analyzing an acquisition. Be consistent about which value is being used when comparing properties.
If annual NOI is $42,000 and property value is $600,000, the cap rate is $42,000 divided by $600,000, or 7%.
Cap rate provides a way to compare property income relative to property value. A higher cap rate does not automatically mean a better investment.
Cap rates can reflect differences in market risk, property condition, location, renter stability, growth expectations, property type, and operating assumptions.
| Cap Rate Calculation | Amount |
|---|---|
| Annual NOI | $42,000 |
| Property value | $600,000 |
| Cap rate | 7.0% |
NOI Margin
NOI margin shows what percentage of effective gross income remains after operating expenses.
The basic formula is NOI Margin = NOI / Effective Gross Income.
Using the example above, $42,000 divided by $72,000 equals 58.3%.
NOI margin can help landlords compare operating efficiency between properties or across time. There is no single universally good NOI margin because property types and markets differ.
How to Improve Rental Property NOI
NOI improves by increasing property operating revenue, reducing operating expenses, or both.
Income strategies may include reducing unnecessary vacancy, improving rent collection, reviewing market rents, adding appropriate parking or storage income, reducing avoidable concessions, recovering eligible utility costs, or adding legitimate ancillary revenue.
Expense strategies may include reviewing insurance costs, reducing unnecessary utility consumption, performing preventive maintenance, comparing vendor pricing, addressing recurring repair problems, reviewing management costs, and monitoring property tax assessments where appropriate.
Cutting necessary maintenance may temporarily reduce expenses but can create larger costs, vacancies, renter dissatisfaction, and property deterioration later.
Common NOI Calculation Mistakes
NOI is only useful when income and expenses are measured consistently.
- Deducting mortgage principal.
- Deducting mortgage interest.
- Including refundable security deposits as income.
- Ignoring vacancy.
- Ignoring unpaid rent or collection losses.
- Treating capital expenditures as normal operating expenses.
- Excluding legitimate operating expenses to make NOI look higher.
- Using inconsistent categories between properties.
- Mixing personal expenses with property expenses.
- Confusing NOI with cash flow.
- Confusing NOI with taxable income.
- Comparing NOI from different periods without accounting for timing or unusual events.
- Using projected rents while using historical expenses without clearly identifying the assumptions.
Actual NOI vs. Projected NOI
Landlords and investors may encounter both actual NOI and projected NOI.
Actual NOI is calculated using actual income and operating expenses from a historical period. Projected NOI is calculated using assumptions about future rent, vacancy, expenses, or property operations.
Projected NOI may assume higher future rents, lower vacancy, reduced expenses, new ancillary income, or completed renovations.
Projected NOI can be useful for planning, but it should not be confused with historical performance. When evaluating an investment, landlords should understand which numbers are actual and which depend on assumptions.
When reviewing a property for purchase, ask whether advertised NOI is historical, trailing-12-month, annualized, pro forma, or stabilized NOI.
Trailing-12-Month NOI
A trailing-12-month, or T-12, NOI calculation uses actual income and operating expenses from the most recent 12 months. It can provide a more current view than a prior calendar-year statement, although unusual expenses, vacancies, rent changes, or one-time events should still be reviewed.
NOI calculated from a shorter period may sometimes be annualized for comparison purposes, but annualized results can be misleading when income or expenses are seasonal or the period contains unusual activity.
How PropioLedger Helps Track the Numbers Behind NOI
PropioLedger helps landlords organize rental income, property expenses, payments, renter balances, cash flow, and property performance in a rental-specific workflow.
Because NOI depends on reliable income and operating-expense data, keeping transactions consistently categorized by property makes it easier to understand the numbers behind property performance.
In PropioLedger, landlords can review rental income, property expenses, payment activity, renter balances, cash flow reports, accounting reports, expense analysis, and property profitability reports. The Accounting Report and Property Profitability Report include net operating income based on recorded rental income and property expenses.
PropioLedger should not be treated as a full general accounting system, a formal financial-statement platform, or a substitute for professional accounting, tax, legal, financial, or investment advice.
Track the Income and Expenses Behind NOI
NOI depends on clean property-level records. PropioLedger helps landlords organize rental income, property expenses, payment activity, cash flow, renter balances, and property performance in one rental-focused workflow.
Educational Disclaimer
This guide is for general educational purposes and is not tax, accounting, legal, financial, or investment advice. NOI presentation, income classification, operating-expense classification, capital expenditure treatment, depreciation, financing costs, tax treatment, and investment analysis depend on individual circumstances, reporting purpose, accounting method, applicable rules, and professional judgment. Landlords should consult a qualified accountant, tax professional, attorney, financial advisor, or investment professional for guidance specific to their situation.