Analyze cash flow, Cap Rate, and Cash on Cash Return.
Investment Analysis
Monthly Principal & Interest:$0.00
Total Monthly Expenses:$0.00
Net Operating Income (NOI – Annual):$0.00
Monthly Cash Flow:$0.00
Cap Rate:0.00%
Cash on Cash Return (ROI):0.00%
function calculateROI() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('purchasePrice').value);
var down = parseFloat(document.getElementById('downPayment').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var term = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var vacancy = parseFloat(document.getElementById('vacancyRate').value);
var tax = parseFloat(document.getElementById('annualTax').value);
var insurance = parseFloat(document.getElementById('annualInsurance').value);
var hoa = parseFloat(document.getElementById('monthlyHOA').value);
var maint = parseFloat(document.getElementById('maintenance').value);
// Validation
if (isNaN(price) || isNaN(down) || isNaN(rent) || isNaN(tax) || isNaN(insurance)) {
alert("Please fill in all required numeric fields (Price, Down Payment, Rent, Taxes, Insurance).");
return;
}
// Set defaults if empty but not NaN (though input type number usually returns empty string if not a number)
if (isNaN(rate)) rate = 0;
if (isNaN(term)) term = 30;
if (isNaN(vacancy)) vacancy = 0;
if (isNaN(hoa)) hoa = 0;
if (isNaN(maint)) maint = 0;
// 2. Calculate Mortgage (Principal + Interest)
var loanAmount = price – down;
var monthlyRate = rate / 100 / 12;
var numberOfPayments = term * 12;
var mortgagePayment = 0;
if (rate > 0 && loanAmount > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// 3. Calculate Operating Expenses
// Vacancy Loss
var monthlyVacancyLoss = rent * (vacancy / 100);
// Maintenance/CapEx
var monthlyMaintenance = rent * (maint / 100);
// Taxes & Insurance (Monthly)
var monthlyTax = tax / 12;
var monthlyIns = insurance / 12;
var totalMonthlyExpenses = mortgagePayment + monthlyTax + monthlyIns + hoa + monthlyVacancyLoss + monthlyMaintenance;
var totalOperatingExpenses = monthlyTax + monthlyIns + hoa + monthlyVacancyLoss + monthlyMaintenance; // Excludes mortgage for NOI
// 4. Calculate Cash Flow
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// 5. Calculate NOI (Net Operating Income)
// NOI = Annual Rent – Annual Operating Expenses (Excluding Mortgage)
var annualRent = rent * 12;
var annualOperatingExpenses = totalOperatingExpenses * 12;
var noi = annualRent – annualOperatingExpenses;
// 6. Calculate Cap Rate
// Cap Rate = NOI / Purchase Price
var capRate = (noi / price) * 100;
// 7. Calculate Cash on Cash ROI
// CoC = Annual Cash Flow / Total Cash Invested
// Assuming Cash Invested = Down Payment (simplified, ignoring closing costs for this tool)
var cashInvested = down;
var cashOnCash = 0;
if (cashInvested > 0) {
cashOnCash = (annualCashFlow / cashInvested) * 100;
} else if (cashInvested === 0 && annualCashFlow > 0) {
cashOnCash = Infinity;
}
// 8. Update UI
document.getElementById('resMortgage').innerText = "$" + mortgagePayment.toFixed(2);
document.getElementById('resTotalExp').innerText = "$" + totalMonthlyExpenses.toFixed(2);
document.getElementById('resNOI').innerText = "$" + noi.toFixed(2);
var cfElement = document.getElementById('resCashFlow');
cfElement.innerText = "$" + monthlyCashFlow.toFixed(2);
if(monthlyCashFlow >= 0) {
cfElement.className = "result-value positive-cf";
} else {
cfElement.className = "result-value negative-cf";
}
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
var cocElement = document.getElementById('resCOC');
cocElement.innerText = cashOnCash.toFixed(2) + "%";
if(cashOnCash >= 0) {
cocElement.className = "result-value positive-cf";
} else {
cocElement.className = "result-value negative-cf";
}
document.getElementById('results').style.display = 'block';
}
Understanding Your Rental Property Investment
Investing in real estate is one of the most reliable ways to build wealth, but it requires precise calculation to ensure profitability. This Rental Property ROI Calculator helps investors analyze a potential deal by breaking down the expenses, cash flow, and return on investment metrics.
Key Metrics Explained
Cash Flow: This is the profit you take home each month after all expenses (mortgage, taxes, insurance, repairs) are paid. Positive cash flow is essential for a sustainable investment.
Cap Rate (Capitalization Rate): This metric measures the natural rate of return on the property, independent of financing. It is calculated as Net Operating Income (NOI) / Purchase Price. It helps compare the profitability of different properties.
Cash on Cash Return (CoC ROI): This measures the return on the actual cash you invested (down payment). It is calculated as Annual Cash Flow / Total Cash Invested. This is often considered the most important metric for investors using leverage.
Example Calculation
Let's say you are looking at a single-family home with the following numbers:
Purchase Price: $250,000
Down Payment: $50,000 (20%)
Loan: 30-year fixed at 6.5% interest
Rental Income: $2,200 per month
Annual Expenses: $3,000 Taxes, $1,200 Insurance
Using our calculator, you would find that your monthly mortgage payment (Principal & Interest) is approximately $1,264. After accounting for taxes, insurance, and a 10% budget for maintenance and vacancy, your monthly cash flow might be around $236. This results in a Cash on Cash return of roughly 5.6%.
Use the tool above to adjust variables like the rental rate or down payment to see how they impact your bottom line before you make an offer.