Estimate monthly cash flow, mortgage payment, cap rate, and cash-on-cash return for a rental property based on purchase price, financing terms, rent, and operating expenses.
Quick Facts
Cap rate
Net operating income ÷ purchase price
NOI is rent minus operating expenses, before the mortgage payment — cap rate reflects the return as if bought in cash.
Cash-on-cash return
Annual cash flow ÷ cash invested
Measures return on your actual down payment, so it moves with how the deal is financed.
Your Results
Calculated
Monthly cash flow
—
Rent minus expenses and mortgage payment
Monthly mortgage payment
—
Principal & interest on the loan
Cap rate
—
Net operating income ÷ purchase price
Cash-on-cash return
—
Annual cash flow ÷ down payment
Ready
Enter the purchase price, financing terms, rent, and expenses, then press Calculate.
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How to use this calculator
Enter the property's purchase price, your down payment percentage, the mortgage interest rate and loan term, the rent you expect to collect each month, and your estimated monthly operating expenses (property tax, insurance, maintenance, HOA dues, vacancy allowance, and management fees combined, excluding the mortgage). Click Calculate to see the monthly mortgage payment, monthly cash flow, cap rate, and cash-on-cash return. Click Clear to reset all fields to the example values.
Understanding the inputs
Down payment percentage determines how much you finance: a 20% down payment on a $350,000 property means a $70,000 down payment and a $280,000 loan. The mortgage interest rate and loan term set the monthly principal-and-interest payment using the standard amortization formula. Monthly operating expenses should exclude the mortgage payment itself — that is calculated separately — but should include everything else it costs to hold the property, including an allowance for vacant months.
Interpreting the results
Monthly cash flow is what is left over after rent covers expenses and the mortgage payment — the number that determines whether the property pays for itself. Cap rate shows the property's return independent of financing (net operating income divided by purchase price), useful for comparing deals on an apples-to-apples basis. Cash-on-cash return shows the return on the cash you actually invested (the down payment), which is what most buy-and-hold investors use to compare financed deals against other investments.
Frequently Asked Questions
What is cap rate and why does it matter?
Cap rate (capitalization rate) is net operating income divided by purchase price, expressed as a percentage. It measures a property's return as if bought entirely in cash, so it excludes the mortgage payment. Cap rate lets you compare properties of different prices on a common scale, but on its own it says nothing about how financing affects your actual cash flow.
What counts as a monthly operating expense?
Operating expenses are the recurring costs of owning and running the property that are not the mortgage payment: property tax, landlord insurance, routine maintenance and repairs, HOA dues, property management fees, and a vacancy allowance for months without a tenant. Leaving out a vacancy allowance is the most common way investors overstate cash flow.
What is cash-on-cash return?
Cash-on-cash return is annual cash flow (after the mortgage payment) divided by the actual cash you put in — typically the down payment. Unlike cap rate, it reflects financing: a larger loan means less cash invested, which can raise the percentage return even if the dollar cash flow is similar.
Does this calculator account for taxes and appreciation?
No. This calculator models operating cash flow, cap rate, and cash-on-cash return from the price, financing terms, rent, and expenses you enter. It does not project property appreciation, resale proceeds, depreciation deductions, or income taxes — those require separate analysis and vary by situation, so consult a tax professional for after-tax planning.
Practical Guide for Investment Property Calculator
Investment Property Calculator is most useful when the inputs reflect the situation you are actually planning around, not a best-case estimate. Treat the result as a decision aid: it gives you a structured way to compare assumptions, spot outliers, and decide what to verify next. For Finance work, the most important review lens is cash flow, timing, rates, risk tolerance, and the reliability of each assumption.
Start with a baseline run using values you can defend. Then change one assumption at a time and watch which output moves the most. If one input dominates the result, spend your verification time there first. If several inputs have similar influence, use a conservative scenario and an optimistic scenario to create a practical range instead of relying on a single exact number.
Before acting on the result, compare the result with bank statements, invoices, amortization schedules, or accounting exports before making a commitment. This is especially important when the calculator supports a purchase, project plan, performance target, or operational decision. The calculator can make the math consistent, but the quality of the conclusion still depends on current data, clear units, and assumptions that match your real constraints.
When the output looks surprising, slow down and inspect each input in order. A small change in one high-leverage field can move the final number more than several low-leverage fields combined. For Investment Property Calculator, that means you should first confirm the value with the greatest scale, then confirm the value with the greatest uncertainty, then rerun the calculator with conservative and optimistic assumptions. This sequence turns the calculator from a single answer into a practical decision range.
Review Checklist
Confirm every input uses the unit and time period requested by the calculator.
Run a low, expected, and high scenario so the answer has a useful range.
Check whether rounding or a missing decimal place changes the decision.
Update the calculation monthly or whenever income, rates, expenses, or balances change materially.