Analyzing a potential real estate investment requires accurate data. Use this calculator to determine the monthly cash flow, Cash on Cash (CoC) return, and Cap Rate of a rental property. Simply enter the purchase details, expected income, and operating expenses below.
Purchase Information
Income Information
Annual Expenses
Please enter valid positive numbers in all fields.
Total Cash Invested (Down Payment + Closing):$0.00
Monthly Mortgage Payment (P&I):$0.00
Total Monthly Expenses (w/o Mortgage):$0.00
Net Operating Income (NOI / Month):$0.00
Monthly Cash Flow:$0.00
Annual Cash Flow:$0.00
Cash on Cash Return (CoC):0.00%
Cap Rate:0.00%
Understanding Rental Property Investment Metrics
Successful real estate investing relies on understanding the numbers behind the property. While appreciation is a nice bonus, experienced investors focus on cash flow and return on investment (ROI) metrics to ensure the asset is performing well today.
What is Monthly Cash Flow?
Cash Flow is the profit you bring in each month after all operating expenses and mortgage payments have been made. Positive cash flow is essential for maintaining the property and weathering vacancies without dipping into your personal savings. It is calculated as:
The Cash on Cash Return measures the annual return you are making on the actual cash you invested (down payment plus closing costs). It is one of the most important metrics because it allows you to compare real estate returns against other investment vehicles like stocks or bonds.
For example, if you invest $50,000 cash to buy a property and it generates $5,000 in net annual cash flow, your CoC return is 10%. Many investors aim for a CoC return of 8-12% or higher.
What is a Cap Rate?
The Capitalization Rate (Cap Rate) measures the property's natural rate of return assuming it was bought with all cash (no loan). It helps compare the profitability of different properties regardless of how they are financed. It is calculated by dividing the annual Net Operating Income (NOI) by the purchase price.
function calculateCashFlow() {
// Get Input Values
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPaymentPercent = parseFloat(document.getElementById('downPayment').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var loanTermYears = parseFloat(document.getElementById('loanTerm').value);
var monthlyRent = parseFloat(document.getElementById('monthlyRent').value);
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value);
var propertyTaxYear = parseFloat(document.getElementById('propertyTax').value);
var insuranceYear = parseFloat(document.getElementById('insurance').value);
var maintenancePercent = parseFloat(document.getElementById('maintenance').value);
var managementPercent = parseFloat(document.getElementById('managementFee').value);
var hoaMonth = parseFloat(document.getElementById('hoa').value);
var closingCosts = parseFloat(document.getElementById('closingCosts').value);
// Validation
if (isNaN(price) || isNaN(downPaymentPercent) || isNaN(interestRate) || isNaN(loanTermYears) ||
isNaN(monthlyRent) || isNaN(vacancyRate) || isNaN(propertyTaxYear) ||
isNaN(insuranceYear) || isNaN(maintenancePercent) || isNaN(managementPercent) ||
isNaN(hoaMonth) || isNaN(closingCosts)) {
document.getElementById('error-message').style.display = 'block';
document.getElementById('results-area').style.display = 'none';
return;
} else {
document.getElementById('error-message').style.display = 'none';
}
// Calculations
// 1. Loan Calculations
var downPaymentAmount = price * (downPaymentPercent / 100);
var loanAmount = price – downPaymentAmount;
// Mortgage Payment (Principal & Interest)
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = loanTermYears * 12;
var mortgagePayment = 0;
if (interestRate === 0) {
mortgagePayment = loanAmount / numberOfPayments;
} else {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// 2. Income Calculations
var vacancyLoss = monthlyRent * (vacancyRate / 100);
var effectiveGrossIncome = monthlyRent – vacancyLoss;
// 3. Expense Calculations
var monthlyTax = propertyTaxYear / 12;
var monthlyInsurance = insuranceYear / 12;
var monthlyMaintenance = monthlyRent * (maintenancePercent / 100); // Usually based on gross rent
var monthlyManagement = effectiveGrossIncome * (managementPercent / 100); // Usually based on collected rent
var totalMonthlyExpenses = monthlyTax + monthlyInsurance + monthlyMaintenance + monthlyManagement + hoaMonth;
// 4. Returns Calculations
var monthlyNOI = effectiveGrossIncome – totalMonthlyExpenses; // Net Operating Income
var monthlyCashFlow = monthlyNOI – mortgagePayment;
var annualCashFlow = monthlyCashFlow * 12;
var annualNOI = monthlyNOI * 12;
var totalCashInvested = downPaymentAmount + closingCosts;
var cashOnCashReturn = 0;
if (totalCashInvested > 0) {
cashOnCashReturn = (annualCashFlow / totalCashInvested) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// Formatting Output
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
});
document.getElementById('res-cash-invested').innerText = formatter.format(totalCashInvested);
document.getElementById('res-mortgage').innerText = formatter.format(mortgagePayment);
document.getElementById('res-expenses').innerText = formatter.format(totalMonthlyExpenses);
document.getElementById('res-noi').innerText = formatter.format(monthlyNOI);
document.getElementById('res-cashflow').innerText = formatter.format(monthlyCashFlow);
document.getElementById('res-annual-cashflow').innerText = formatter.format(annualCashFlow);
// Coloring Cash Flow
var cashFlowElement = document.getElementById('res-cashflow');
if (monthlyCashFlow >= 0) {
cashFlowElement.style.color = '#27ae60';
} else {
cashFlowElement.style.color = '#c0392b';
}
document.getElementById('res-coc').innerText = cashOnCashReturn.toFixed(2) + '%';
document.getElementById('res-cap').innerText = capRate.toFixed(2) + '%';
// Show Results
document.getElementById('results-area').style.display = 'block';
}