Rental property calculator — with the math showing.
Enter a deal and watch the underwrite happen: income to NOI, financing to cash flow, and the return ratios lenders ask about — each with its derivation in the open. No signup, no login wall.
Every figure above is computed by the same audited engine that powers BuyBox — audited against industry-standard real-estate math. Estimates, not investment advice.
This is one metric. BuyBox runs the whole underwrite — verdict in about 30 seconds.
How this rental property calculator works
The underwrite runs in the standard order: gross rent, minus a vacancy allowance, gives effective gross income; subtracting operating expenses (management, repairs, capital-expenditure reserves, insurance, taxes) gives NOI — the property's earning power before financing. Debt service then turns NOI into cash flow, and the ratios — cap rate, cash-on-cash, DSCR — express that result against price, cash invested, and debt.
Two honest notes. First, the output is only as good as the rent and expense assumptions you enter — this page doesn't look up rents or taxes for you. Second, percentage reserves are a screening convention; a real underwrite itemizes. The full walkthrough of every step lives in how to analyze a rental property.