function calculateRentalROI() {
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value) || 0;
var rate = parseFloat(document.getElementById('interestRate').value) || 0;
var term = parseFloat(document.getElementById('loanTerm').value) || 30;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var taxes = parseFloat(document.getElementById('propertyTaxes').value) || 0;
var insurance = parseFloat(document.getElementById('insurance').value) || 0;
var expPercent = parseFloat(document.getElementById('otherExpPercent').value) || 0;
// Calculations
var downPayment = price * (downPercent / 100);
var loanAmount = price – downPayment;
var monthlyRate = (rate / 100) / 12;
var numPayments = term * 12;
// Mortgage P&I
var monthlyMortgage = 0;
if (rate > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
} else {
monthlyMortgage = loanAmount / numPayments;
}
// Monthly Expenses
var monthlyTaxes = taxes / 12;
var monthlyInsurance = insurance / 12;
var monthlyMaintVac = rent * (expPercent / 100);
var totalMonthlyExpenses = monthlyMortgage + monthlyTaxes + monthlyInsurance + monthlyMaintVac;
// ROI Metrics
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
var cashOnCash = (annualCashFlow / downPayment) * 100;
var annualNOI = (rent * 12) – (taxes + insurance + (monthlyMaintVac * 12));
var capRate = (annualNOI / price) * 100;
// Display
document.getElementById('roi-results').style.display = 'block';
document.getElementById('resCashFlow').innerText = '$' + monthlyCashFlow.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resCoC').innerText = cashOnCash.toFixed(2) + '%';
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + '%';
document.getElementById('resMortgage').innerText = '$' + monthlyMortgage.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resNOI').innerText = '$' + annualNOI.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resInvestment').innerText = '$' + downPayment.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
if(monthlyCashFlow < 0) {
document.getElementById('resCashFlow').style.color = '#e74c3c';
} else {
document.getElementById('resCashFlow').style.color = '#2980b9';
}
}
How to Calculate Rental Property ROI
Investing in real estate requires a clear understanding of your potential returns. This Rental Property ROI Calculator helps you analyze a property's profitability by breaking down the key financial metrics that professional investors use.
Understanding the Key Metrics
Monthly Cash Flow: The amount of profit left over after all expenses, including the mortgage, taxes, insurance, and maintenance, have been paid. Positive cash flow is essential for long-term sustainability.
Cap Rate (Capitalization Rate): Calculated as Net Operating Income (NOI) divided by the Purchase Price. It allows you to compare different properties without considering mortgage financing.
Cash on Cash Return: This is the ratio of your annual pre-tax cash flow to the total amount of cash invested (usually your down payment). It tells you exactly how hard your liquid cash is working for you.
Net Operating Income (NOI): The total income generated by the property minus all necessary operating expenses, excluding mortgage payments.
Real Estate ROI Example
Imagine you purchase a single-family home for $300,000 with a 20% down payment ($60,000). At a 6.5% interest rate, your mortgage might be around $1,517. If you rent the property for $2,500 and pay $500 in taxes, insurance, and maintenance, your monthly cash flow would be roughly $483.
In this scenario, your Annual Cash Flow would be $5,796, resulting in a Cash on Cash Return of 9.66%. This provides a much clearer picture of the investment than simply looking at the monthly rent alone.
Pro Tips for Better ROI
Account for Vacancy: Never assume 100% occupancy. Always set aside 5-10% of rent for potential vacancies.
Maintenance Reserves: Older properties require more upkeep. Budgeting 1% of the property value per year for maintenance is a safe rule of thumb.
Location Matters: A lower Cap Rate in a high-demand area might be better than a high Cap Rate in a declining neighborhood due to potential appreciation.