Analyze the profitability of your real estate investment instantly.
Purchase & Loan Details
30 Years
15 Years
10 Years
Income & Expenses
Monthly Principal & Interest:–
Total Monthly Expenses:–
Net Operating Income (Monthly):–
Monthly Cash Flow:–
Cash on Cash ROI:–
Cap Rate:–
function calculateRentalROI() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('rp_price').value) || 0;
var downPayment = parseFloat(document.getElementById('rp_down_payment').value) || 0;
var interestRate = parseFloat(document.getElementById('rp_interest_rate').value) || 0;
var termYears = parseInt(document.getElementById('rp_loan_term').value) || 30;
var closingCosts = parseFloat(document.getElementById('rp_closing_costs').value) || 0;
var rent = parseFloat(document.getElementById('rp_rent').value) || 0;
var vacancyRate = parseFloat(document.getElementById('rp_vacancy').value) || 0;
var annualTax = parseFloat(document.getElementById('rp_property_tax').value) || 0;
var annualInsurance = parseFloat(document.getElementById('rp_insurance').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('rp_hoa').value) || 0;
var monthlyMaintenance = parseFloat(document.getElementById('rp_maintenance').value) || 0;
// 2. Mortgage Calculation
var loanAmount = price – downPayment;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = termYears * 12;
var monthlyPI = 0;
if (monthlyRate > 0) {
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
monthlyPI = loanAmount / numberOfPayments;
}
// 3. Expense Calculation
var vacancyCost = rent * (vacancyRate / 100);
var monthlyTax = annualTax / 12;
var monthlyInsurance = annualInsurance / 12;
var totalMonthlyExpenses = monthlyPI + monthlyTax + monthlyInsurance + monthlyHOA + monthlyMaintenance + vacancyCost;
var operatingExpenses = monthlyTax + monthlyInsurance + monthlyHOA + monthlyMaintenance + vacancyCost; // Excluding mortgage for NOI
// 4. ROI Metrics
var monthlyNOI = rent – operatingExpenses;
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
var annualNOI = monthlyNOI * 12;
var totalInvestment = downPayment + closingCosts;
var cashOnCash = 0;
if (totalInvestment > 0) {
cashOnCash = (annualCashFlow / totalInvestment) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// 5. Display Results
document.getElementById('rp-results').style.display = 'block';
var currencyFormat = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
document.getElementById('res_mortgage').innerText = currencyFormat.format(monthlyPI);
document.getElementById('res_expenses').innerText = currencyFormat.format(totalMonthlyExpenses);
document.getElementById('res_noi').innerText = currencyFormat.format(monthlyNOI);
var cfElement = document.getElementById('res_cashflow');
cfElement.innerText = currencyFormat.format(monthlyCashFlow);
if (monthlyCashFlow >= 0) {
cfElement.className = 'rp-result-value rp-highlight';
} else {
cfElement.className = 'rp-result-value rp-highlight-neg';
}
document.getElementById('res_coc').innerText = cashOnCash.toFixed(2) + '%';
document.getElementById('res_cap').innerText = capRate.toFixed(2) + '%';
}
Analyzing Real Estate Investments: Understanding the Numbers
Investing in rental property can be a powerful vehicle for wealth generation, but success depends entirely on the numbers. Unlike emotional home buying, investment property requires a cold, hard look at Cash Flow, ROI, and Cap Rates. This Rental Property Cash Flow Calculator is designed to help you make data-driven decisions.
1. What is Cash Flow?
Cash flow is the net amount of money left over after all operating expenses and debt service (mortgage) have been paid. It is the lifeblood of any rental investment. Positive cash flow means the property pays for itself and puts money in your pocket every month. Negative cash flow ("being underwater") means you are paying out of pocket to hold the asset.
While cash flow tells you the dollar amount you earn, Cash on Cash Return tells you how hard your money is working. It measures the annual return on the actual cash you invested (Down Payment + Closing Costs), rather than the total value of the property. This is crucial because it accounts for the power of leverage.
For example, if you invest $50,000 to buy a $250,000 property and earn $5,000 a year in cash flow, your Cash on Cash return is 10%.
3. Capitalization Rate (Cap Rate)
The Cap Rate measures the natural rate of return of the property assuming you bought it with all cash (no mortgage). It helps you compare the profitability of one property against another, regardless of how they are financed. A higher Cap Rate generally indicates a higher potential return, but often comes with higher risk.
Formula: Net Operating Income (NOI) / Purchase Price = Cap Rate
Common Expenses Investors Forget
When using this calculator, ensure you aren't underestimating expenses. Beginners often forget:
Vacancy Rates: Properties won't be rented 365 days a year. Use 5-8% as a standard buffer.
CapEx (Capital Expenditures): Big-ticket items like roofs and HVAC systems eventually need replacement. Budgeting monthly for these future costs is essential.
Property Management: Even if you self-manage, your time has value. Factor in 8-10% to see if the deal still works if you had to hire a manager later.
Use the calculator above to adjust your purchase price, down payment, and expense estimates to find the "sweet spot" where your investment goals are met.