NOI Calculator

An NOI calculator estimates net operating income by subtracting vacancy and operating expenses from a property's income. Real estate investors use NOI to compare rentals, evaluate deal quality, estimate cap rate, and understand how much income a property produces before financing costs are applied.

An NOI calculator measures the income a property produces after normal operating expenses are deducted, but before mortgage payments, income taxes, depreciation, and major financing decisions are considered. NOI stands for net operating income, and it is one of the most common underwriting metrics in rental and commercial real estate. By focusing on operations instead of loan structure, the calculation gives investors a cleaner way to compare the underlying performance of two different properties.

In practice, an NOI calculator starts with gross rental income, adjusts for vacancy, adds any recurring non-rent income, and then subtracts annual operating costs such as taxes, insurance, management, utilities, and maintenance. The result shows how much income the property itself is generating from day-to-day operations. That matters because a property can look attractive on gross rent alone while still producing weak operating income once realistic expenses are included.

Investors, lenders, brokers, and owners all use an NOI calculator during acquisition analysis, refinance review, annual budgeting, and portfolio benchmarking. It helps answer practical questions such as whether rent increases are offsetting rising expenses, whether a property is strong enough to support new debt, and how much value may be created by operational improvements. Because NOI connects income to valuation, cap rate, and lender underwriting, it remains a core real estate metric for both small rentals and larger commercial assets.

1. Enter annual gross rental income based on current leases or a realistic stabilized rent estimate.
2. Add a vacancy rate so the tool can reduce projected rent for normal turnover, downtime, or credit loss.
3. Input other recurring income such as parking, laundry, storage, pet fees, or reimbursements.
4. Enter annual operating expenses, including taxes, insurance, repairs, management, utilities, HOA fees, and any additional operating costs.
5. Add an optional CapEx reserve if you want a more conservative planning view of recurring property costs.
6. Click Calculate to see vacancy loss, effective gross income, total operating expenses, and net operating income.

NOI = (Gross Rental Income - Vacancy Loss + Other Income) - Operating Expenses

• Vacancy loss equals gross rent multiplied by the vacancy rate.
• Other income includes recurring items outside base rent.
• Operating expenses include costs required to run the property.
• Debt service and income taxes are not part of NOI.

Gross Rental Income

This is the annual rent the property could collect if fully occupied. It is the starting point for the NOI calculation and should reflect realistic market rent.

Vacancy Loss

Vacancy loss reduces gross rent for expected turnover, downtime, and nonpayment. A higher vacancy assumption lowers effective income even when asking rents look strong.

Effective Gross Income

Effective gross income is gross rent after vacancy plus other recurring income. It represents what the property is more likely to collect in an average year.

Operating Expenses

These are the recurring costs required to own and operate the property, such as taxes, insurance, repairs, management, utilities, and HOA dues.

Net Operating Income

NOI is the income remaining after operating expenses are subtracted from effective gross income. It is commonly used in cap rate, DSCR, valuation, and lender review.

Assume the following annual inputs for a small multifamily property:

• Gross rental income: $120,000
• Vacancy rate: 5%
• Other income: $6,000
• Property taxes: $9,000
• Insurance, repairs, management, and utilities: $18,200 combined

Step 1: Calculate vacancy loss. $120,000 x 5% = $6,000.

Step 2: Calculate effective gross income. $120,000 - $6,000 + $6,000 = $120,000.

Step 3: Add total operating expenses. $9,000 + $18,200 = $27,200.

Final result: NOI is $120,000 - $27,200 = $92,800, or about $7,733 per month. That result suggests the property is producing meaningful operating income before debt service, which can then be used to estimate cap rate, debt coverage, or investment value.