Please enter valid positive numbers for all fields.
Total Cash Invested (Down Payment):$0.00
Loan Amount:$0.00
Monthly Mortgage (P&I):$0.00
Total Monthly Expenses:$0.00
Estimated Monthly Cash Flow$0.00
Cap Rate0.00%
Cash on Cash Return0.00%
function calculateRental() {
// Get inputs
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var years = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var taxes = parseFloat(document.getElementById('annualTaxes').value);
var insurance = parseFloat(document.getElementById('annualInsurance').value);
var hoa = parseFloat(document.getElementById('monthlyHOA').value);
// Validation
if (isNaN(price) || isNaN(downPercent) || isNaN(rate) || isNaN(years) ||
isNaN(rent) || isNaN(taxes) || isNaN(insurance) || isNaN(hoa)) {
document.getElementById('errorMsg').style.display = 'block';
document.getElementById('resultsSection').style.display = 'none';
return;
} else {
document.getElementById('errorMsg').style.display = 'none';
document.getElementById('resultsSection').style.display = 'block';
}
// Calculations
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
// Mortgage P&I
var monthlyRate = rate / 100 / 12;
var numPayments = years * 12;
var mortgagePayment = 0;
if (rate === 0) {
mortgagePayment = loanAmount / numPayments;
} else {
mortgagePayment = (loanAmount * monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
}
// Monthly Expenses
var monthlyTax = taxes / 12;
var monthlyIns = insurance / 12;
var totalMonthlyExpenses = mortgagePayment + monthlyTax + monthlyIns + hoa;
// Cash Flow
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// NOI (Net Operating Income) = Income – Operating Expenses (Excluding Financing)
// Operating Expenses for NOI = Tax + Insurance + HOA
var annualOperatingExpenses = taxes + insurance + (hoa * 12);
var annualNOI = (rent * 12) – annualOperatingExpenses;
// Metrics
var capRate = (annualNOI / price) * 100;
var cashOnCash = (annualCashFlow / downPaymentAmount) * 100;
// Display Results
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
document.getElementById('resDownPayment').innerText = formatter.format(downPaymentAmount);
document.getElementById('resLoanAmount').innerText = formatter.format(loanAmount);
document.getElementById('resMortgage').innerText = formatter.format(mortgagePayment);
document.getElementById('resTotalExpenses').innerText = formatter.format(totalMonthlyExpenses);
var cashFlowElem = document.getElementById('resCashFlow');
cashFlowElem.innerText = formatter.format(monthlyCashFlow);
cashFlowElem.style.color = monthlyCashFlow >= 0 ? '#27ae60' : '#c0392b';
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
// Handle Infinity case for CoC if 0 down
if (downPaymentAmount === 0) {
document.getElementById('resCoC').innerText = "Infinite";
} else {
document.getElementById('resCoC').innerText = cashOnCash.toFixed(2) + "%";
}
}
Understanding Rental Property Analysis
Investing in real estate is a powerful way to build wealth, but the difference between a profitable asset and a financial burden often comes down to the numbers. Using a reliable Rental Property ROI Calculator is essential for investors to evaluate the potential performance of a prospective purchase. This tool helps you look past the listing price and understand the actual cash flow dynamics.
Key Metrics Explained
When analyzing a rental property, three primary metrics indicate success:
Cash Flow: This is the net amount of money left in your pocket each month after all operating expenses and mortgage payments are made. Positive cash flow ensures the property pays for itself and generates income.
Cap Rate (Capitalization Rate): This percentage represents the rate of return on a real estate investment property based on the income that the property is expected to generate, excluding financing costs. It allows you to compare the raw profitability of different properties regardless of how they are financed.
Cash on Cash (CoC) Return: This metric measures the annual return on the actual cash you invested (down payment and closing costs). It is crucial for understanding how hard your specific capital is working for you.
How to Estimate Expenses
One of the most common mistakes new investors make is underestimating expenses. Beyond the mortgage principal and interest, you must account for property taxes, homeowner's insurance, and HOA fees. Experienced investors also set aside funds for vacancy (periods where the unit is empty) and capital expenditures (major repairs like a new roof or HVAC system). While this calculator covers fixed monthly costs, always leave a buffer in your cash flow analysis for unexpected repairs.
Optimizing Your Investment Strategy
By adjusting variables such as the down payment percentage or loan term in the calculator above, you can see how different financing structures impact your monthly cash flow. Often, a higher down payment can turn a negative cash flow property into a positive one, though it may lower your Cash on Cash return. Finding the right balance fits your personal investment goals.