Income Approach Calculator Formula

Understand the math behind the income approach calculator. Each variable explained with a worked example.

Formulas Used

Indicated Property Value

property_value = noi / (market_cap_rate / 100)

Net Operating Income

net_operating_income = noi

Effective Gross Income

effective_gross_income = effective_income

Variables

VariableDescriptionDefault
gross_incomeGross Annual Income(USD)60000
vacancy_pctVacancy Allowance(%)5
operating_expensesAnnual Operating Expenses(USD)18000
market_cap_rateMarket Cap Rate(%)7
effective_incomeDerived value= gross_income * (1 - vacancy_pct / 100)calculated
noiDerived value= effective_income - operating_expensescalculated

How It Works

Income Approach to Value

The income approach (direct capitalization) converts a property's income stream into a value estimate using a cap rate derived from market data.

Steps

1. Start with gross annual income 2. Subtract vacancy allowance to get effective gross income 3. Subtract operating expenses to get net operating income (NOI) 4. Divide NOI by the market cap rate to get property value

Formula

Value = NOI / Cap Rate

Worked Example

A duplex generates $60,000 gross income, with 5% vacancy, $18,000 expenses, and a 7% market cap rate.

gross_income = 60000vacancy_pct = 5operating_expenses = 18000market_cap_rate = 7
  1. 01Effective gross income: $60,000 x (1 - 0.05) = $57,000
  2. 02Net operating income: $57,000 - $18,000 = $39,000
  3. 03Property value: $39,000 / 0.07 = $557,143

Frequently Asked Questions

When is the income approach used?

The income approach is primarily used for income-producing properties like rentals, apartments, and commercial buildings. It is less useful for owner-occupied homes that do not generate income.

Where does the cap rate come from?

The market cap rate is derived from recent sales of comparable income-producing properties by dividing their NOI by their sale price. It reflects the return investors expect in that market.

What expenses are included in operating expenses?

Operating expenses include property taxes, insurance, management fees, maintenance, utilities (if owner-paid), and reserves. They exclude mortgage payments and depreciation.

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