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Rental Property Calculator

Analyze the annual operating performance of a rental property, estimating Gross Operating Income, Operating Expense Ratio (OER), and Net Operating Income (NOI).

Calculator Panel

Calculation Ready

Enter your values above and click Calculate.

What This Calculator Does

This calculator structures the standard real estate income statement, helping landlords compute real Net Operating Income (NOI) before debt service.

How to Use This Calculator

Enter the purchase price, monthly rent, other monthly income, expected vacancy rate, and annual operating expenses, then click Calculate.

How the Calculation Works

The underlying math engine processes your inputs using exact formulas. This systematic approach ensures professional, institutional-grade calculation precision:

Mathematical Formula

Gross Operating Income (GOI) = (Monthly Rent + Other Income) * 12 * (1 - Vacancy Rate), NOI = GOI - Annual Expenses

Formula Legend:

  • · Vacancy Rate = The expected percentage of time the property sits empty.
  • · Other Income = Parking, laundry, storage, or utility billing.
  • · Annual Expenses = Operating expenditures (taxes, insurance, maintenance, management).

Practical Example

Suppose you buy a property for $250,000, rent it for $2,200/month, earn $100/month in laundry fees, expect a 5% vacancy rate, and pay $8,400 in annual operating expenses:

Step-by-Step Mathematical Walkthrough:

  1. 1 Calculate Potential Gross Income: ($2,200 + $100) * 12 = $27,600.
  2. 2 Subtract 5% Vacancy Allowance: $27,600 * 0.05 = $1,380. Gross Operating Income (GOI) = $27,600 - $1,380 = $26,220.
  3. 3 Calculate Net Operating Income (NOI): $26,220 - $8,400 = $17,820.
  4. 4 Calculate Operating Expense Ratio (OER): ($8,400 / $26,220) * 100 = 32.04%.

Important Assumptions & Notes

  • The vacancy rate is deducted as a percentage of gross potential income.
  • Principal and interest payments are not included in operating expenses.

Common Mistakes or Considerations

  • Forgetting to set aside cash reserves for vacancy and structural maintenance, leading to cash crunches when major repairs are needed.

Frequently Asked Questions

What is the Operating Expense Ratio (OER)?

OER is a metric that measures the efficiency of a property by comparing its total operating expenses to its gross operating income. A lower ratio indicates the property is cheaper and more efficient to run.

Does property management count as an operating expense?

Yes, property management fees (typically 8% to 12% of collected rent) are a standard operating expense and should always be included in your NOI calculations.