Rental Property Cash Flow & ROI Calculator
:root {
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Cash on Cash Return (CoC)
0.00%
Monthly Expenses Breakdown
Principal & Interest:
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Property Tax:
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Insurance:
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Maintenance (Est.):
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Vacancy Reserve:
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Total Monthly Expenses:
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Investment Summary
Total Cash Invested:
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Annual Net Operating Income:
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Understanding Rental Property Cash Flow
Investing in real estate is a powerful way to build wealth, but simply buying a property doesn't guarantee profit. The most critical metric for any buy-and-hold investor is Cash Flow. This calculator helps you determine if a potential rental property is an asset that puts money in your pocket or a liability that takes it out.
How to Use This Calculator
To get the most accurate results, input the following data points specific to your target property:
- Purchase Price & Down Payment: The agreed sale price and the amount of cash you are putting down upfront.
- Loan Details: Your interest rate and loan term (usually 30 years). These determine your mortgage payment.
- Operating Expenses: These include taxes, insurance, and estimates for maintenance. A common rule of thumb is to set aside 5-10% of rent for maintenance.
- Vacancy Rate: Properties aren't rented 365 days a year forever. A 5% vacancy rate accounts for turnover periods where the property sits empty.
Key Metrics Explained
Monthly Cash Flow
This is your "take-home" profit after all expenses, including the mortgage, have been paid. A positive cash flow means the property pays for itself and generates income. A negative cash flow means you must contribute monthly to keep the property running.
Cash on Cash Return (CoC)
This percentage tells you how hard your actual invested cash is working. It is calculated by dividing your Annual Cash Flow by your Total Cash Invested (Down Payment + Closing Costs). Many investors look for a CoC return of 8-12% or higher.
Cap Rate (Capitalization Rate)
The Cap Rate measures the property's natural rate of return without factoring in mortgage financing. It is useful for comparing the profitability of different properties regardless of how they are purchased (cash vs. loan). It is calculated as Net Operating Income (NOI) divided by the Purchase Price.
function calculateRental() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var downPayment = parseFloat(document.getElementById('downPayment').value) || 0;
var rate = parseFloat(document.getElementById('interestRate').value) || 0;
var years = parseFloat(document.getElementById('loanTerm').value) || 0;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var yearlyTax = parseFloat(document.getElementById('propertyTax').value) || 0;
var yearlyInsurance = parseFloat(document.getElementById('insurance').value) || 0;
var maintenancePercent = parseFloat(document.getElementById('maintenance').value) || 0;
var vacancyPercent = parseFloat(document.getElementById('vacancy').value) || 0;
var closingCosts = parseFloat(document.getElementById('closingCosts').value) || 0;
// 2. Calculate Mortgage (Principal + Interest)
var loanAmount = price – downPayment;
var monthlyRate = (rate / 100) / 12;
var numberOfPayments = years * 12;
var monthlyPI = 0;
if (rate > 0) {
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
monthlyPI = loanAmount / numberOfPayments;
}
// 3. Calculate Monthly Expenses
var monthlyTax = yearlyTax / 12;
var monthlyInsurance = yearlyInsurance / 12;
var monthlyMaintenance = rent * (maintenancePercent / 100);
var monthlyVacancy = rent * (vacancyPercent / 100);
var totalMonthlyExpenses = monthlyPI + monthlyTax + monthlyInsurance + monthlyMaintenance + monthlyVacancy;
// 4. Calculate Cash Flow
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// 5. Calculate NOI (Net Operating Income)
// NOI = Income – Operating Expenses (Excluding Mortgage)
var annualOperatingExpenses = yearlyTax + yearlyInsurance + (monthlyMaintenance * 12) + (monthlyVacancy * 12);
var annualNOI = (rent * 12) – annualOperatingExpenses;
// 6. Calculate Returns
var totalInvested = downPayment + closingCosts;
var cashOnCash = 0;
if (totalInvested > 0) {
cashOnCash = (annualCashFlow / totalInvested) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// 7. Format Money Helper
function formatMoney(amount) {
return '$' + amount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
// 8. Update DOM
var cfElement = document.getElementById('monthlyCashFlow');
cfElement.innerText = formatMoney(monthlyCashFlow);
// Color coding logic
if (monthlyCashFlow >= 0) {
cfElement.className = "result-value positive";
} else {
cfElement.className = "result-value negative";
}
document.getElementById('cocReturn').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('capRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resPrincipal').innerText = formatMoney(monthlyPI);
document.getElementById('resTax').innerText = formatMoney(monthlyTax);
document.getElementById('resInsurance').innerText = formatMoney(monthlyInsurance);
document.getElementById('resMaintenance').innerText = formatMoney(monthlyMaintenance);
document.getElementById('resVacancy').innerText = formatMoney(monthlyVacancy);
document.getElementById('resTotalExpenses').innerText = formatMoney(totalMonthlyExpenses);
document.getElementById('resTotalInvested').innerText = formatMoney(totalInvested);
document.getElementById('resNOI').innerText = formatMoney(annualNOI);
}
// Run calculation on load
window.onload = function() {
calculateRental();
};