About this tool
Rental Property ROI Calculator is a free, in-browser tool that evaluates a rental investment with the four numbers landlords actually use: monthly cash flow, cash-on-cash return, net operating income (NOI) and cap rate. All math runs locally — no account, no upload.
NOI is annual rent adjusted for vacancy minus operating expenses (NOI = rent × 12 × (1 − vacancy%) − opex), and cap rate is NOI divided by the purchase price — both deliberately exclude financing so properties can be compared like-for-like. Cash flow then subtracts your annual mortgage payments from NOI, and cash-on-cash divides that by the actual cash you invested (down payment plus closing and rehab costs).
Use it to screen listings quickly: a deal can have a healthy cap rate yet negative cash flow once the loan is added, and this tool shows both sides at once.
Frequently asked questions
Why doesn't NOI include the mortgage?
By convention NOI and cap rate measure the property's operating performance independent of how it is financed, so two buyers with different loans can compare the same building. Financing only enters the cash flow and cash-on-cash figures.
What should I count as operating expenses?
Property tax, insurance, repairs, property management, HOA fees and utilities you pay — everything recurring except the mortgage. Vacancy is handled separately as a percentage of rent (5–8% is a common assumption).
What is a good cash-on-cash return?
It is annual pre-tax cash flow divided by the total cash you put in. Many buy-to-let investors target 6–10%, but the right threshold depends on your market, leverage and risk tolerance — negative means the property costs you money every month.
Is my deal data private?
Yes. All inputs and results stay in your browser; nothing is transmitted or saved.
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