A rental lives or dies on one number: what is left every month after every cost is paid — not the rent, not the landlord's brochure math. Enter the full picture and this calculator returns monthly cash flow, net operating income, cap rate, and cash-on-cash return from the same inputs.
Step 1. Enter the Purchase Price you would actually pay — not the list price you wish existed.
Step 2. Enter the Monthly Rent the property can really collect (check it with the Rent Estimator).
Step 3. Set your Down Payment, Interest Rate, and Loan Term — these build the mortgage payment.
Step 4. Open Advanced and enter taxes, insurance, vacancy, maintenance, management, capital reserves, HOA, and closing costs. Skipping a line does not delete the cost; it deletes your accuracy.
Step 5. Read Monthly Cash Flow first, then cap rate and cash-on-cash to compare this deal against the next one.
Mortgage (P&I): standard amortization on Loan = Price × (1 − Down%), monthly rate = annual rate ÷ 12, over Term × 12 payments.
Effective Gross Income (monthly) = Rent × (1 − Vacancy%).
Operating Expenses (monthly) = Taxes÷12 + Insurance÷12 + Rent × (Maintenance% + Management% + Capital Reserves%) + Other + HOA. Operating expenses exclude the mortgage — that separation is what makes NOI useful.
NOI (yearly) = (Effective Gross Income − Operating Expenses) × 12. Monthly Cash Flow = (NOI − 12 × Mortgage) ÷ 12. Cap Rate = NOI ÷ Purchase Price. Cash-on-Cash = (Cash Flow × 12) ÷ (Down Payment + Closing Costs).
Every line of a rental deal, in the order an underwriter reads it.
Guaranteed-rent programs with real payment standards — and real inspection math.
Buy, rehab, rent, refinance, repeat — where this calculator fits in the sequence.
There is no universal number — it depends on your market, reserves, and goals. What is universal: run it with every expense line filled. A deal that only works with vacancy and maintenance set to zero does not work.
Because rent also pays taxes, insurance, vacancy, repairs, management, and reserves. Rent minus mortgage is a brochure number; rent minus everything is cash flow.
No. Principal paydown builds equity, and appreciation may come — both are real, neither pays this month's bills. Cash flow is the cash number only.
5% is a common planning allowance (about 18 days a year). Use your market's real vacancy if you know it — and never zero.