function calculateRentalROI() {
// Get Input Values
var price = parseFloat(document.getElementById('propPrice').value);
var downPmt = parseFloat(document.getElementById('downPayment').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var years = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var expenses = parseFloat(document.getElementById('monthlyExpenses').value);
// Validation
if (isNaN(price) || isNaN(downPmt) || isNaN(rate) || isNaN(years) || isNaN(rent) || isNaN(expenses)) {
alert("Please enter valid numbers in all fields.");
return;
}
// Loan Logic
var principal = price – downPmt;
var monthlyRate = rate / 100 / 12;
var numPayments = years * 12;
// Mortgage Calculation (Principal + Interest)
var monthlyMortgage = 0;
if (rate > 0) {
monthlyMortgage = principal * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
} else {
monthlyMortgage = principal / numPayments;
}
// Operational Logic
var monthlyNOI = rent – expenses; // Net Operating Income (Monthly)
var annualNOI = monthlyNOI * 12;
var monthlyCashFlow = monthlyNOI – monthlyMortgage;
var annualCashFlow = monthlyCashFlow * 12;
// Return Metrics
var totalInvestment = downPmt; // Keeping it simple (ignoring closing costs for this demo)
var cashOnCash = 0;
if (totalInvestment > 0) {
cashOnCash = (annualCashFlow / totalInvestment) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// Formatting Function
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 0,
maximumFractionDigits: 0,
});
// Display Results
document.getElementById('resultsBox').style.display = 'block';
var mcfEl = document.getElementById('resMonthlyCashFlow');
mcfEl.innerText = formatter.format(monthlyCashFlow);
mcfEl.className = monthlyCashFlow >= 0 ? "result-value positive" : "result-value negative";
var acfEl = document.getElementById('resAnnualCashFlow');
acfEl.innerText = formatter.format(annualCashFlow);
acfEl.className = annualCashFlow >= 0 ? "result-value positive" : "result-value negative";
var cocEl = document.getElementById('resCoC');
cocEl.innerText = cashOnCash.toFixed(2) + "%";
cocEl.className = cashOnCash >= 0 ? "result-value positive" : "result-value negative";
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resMortgage').innerText = formatter.format(monthlyMortgage);
}
Understanding Your Rental Property ROI
Investing in real estate is one of the most reliable ways to build wealth, but simply buying a property and renting it out doesn't guarantee a profit. To succeed, you must understand the numbers behind the deal. This Rental Property ROI Calculator is designed to help investors analyze the profitability of potential real estate purchases by breaking down cash flow, capitalization rates, and returns on investment.
What is Cash on Cash Return?
Cash on Cash (CoC) Return is often considered the most important metric for rental property investors. Unlike general ROI, which might look at the total value of the asset, CoC specifically measures the annual return you make on the actual cash you invested (your down payment and closing costs). For example, if you invest $50,000 in cash and the property generates $5,000 in net annual profit, your Cash on Cash return is 10%. A good CoC return varies by market, but many investors aim for 8-12%.
Understanding Cap Rate vs. Cash Flow
Capitalization Rate (Cap Rate) measures the property's natural rate of return assuming you paid all cash (no mortgage). It is calculated by dividing the Net Operating Income (NOI) by the property's purchase price. This helps you compare the quality of the property itself against other properties, regardless of financing.
Cash Flow, on the other hand, is the money left in your pocket every month after paying operating expenses and the mortgage. Positive cash flow ensures you can hold the property long-term without draining your savings. Our calculator helps you balance these metrics to find deals that offer both immediate income and long-term appreciation.
Key Inputs for Accurate Calculation
Monthly Operating Expenses: Do not underestimate this. Always include property taxes, insurance, HOA fees, maintenance reserves (usually 5-10% of rent), and vacancy allowances (5-8% of rent).
Loan Term: While a 30-year mortgage lowers your monthly payment and increases cash flow, a 15-year mortgage builds equity faster but significantly reduces immediate returns.