How the Property ROI Calculator Works
The calculator analyses a rental property from its price, financing, rent, vacancy and operating expenses. Effective rent = annual rent × (1 − vacancy). Operating expenses sum property tax, insurance, maintenance, management and HOA dues — but never the mortgage, because debt is financing, not an operating cost. Net operating income (NOI) = effective rent − operating expenses. From NOI it derives the cap rate (= net rental yield) = NOI ÷ price × 100, while gross rental yield = annual rent ÷ price × 100. The monthly mortgage payment comes from the shared reducing-balance loan engine; monthly cash flow = (effective rent − operating expenses − mortgage) ÷ 12; and cash-on-cash return = annual cash flow ÷ cash invested (down payment + closing costs) × 100. Every result is produced by a pure, unit-tested function and updates live as you type.
- NOI = annual rent × (1 − vacancy) − operating expenses (mortgage excluded)
- Cap rate = net yield = NOI ÷ price × 100 (unlevered)
- Gross yield = annual rent ÷ price × 100
- Monthly cash flow = (effective rent − expenses − mortgage) ÷ 12
- Cash-on-cash = annual cash flow ÷ (down payment + closing costs) × 100
