Analyze your real estate investment deal in seconds.
Purchase & Loan Details
Income & Expenses
Monthly P&I (Mortgage):$0.00
Total Monthly Expenses:$0.00
Net Operating Income (NOI) / Yr:$0.00
Cap Rate:0.00%
Cash on Cash Return:0.00%
Monthly Cash Flow:$0.00
Understanding Rental Property Cash Flow
Cash flow is the lifeblood of any rental property investment. It represents the net amount of cash moving in and out of your business after all expenses have been paid. A positive cash flow means the property is generating income for you every month, while negative cash flow implies you are losing money to hold the asset.
How This Calculator Works
This tool breaks down the profitability of a real estate deal by analyzing three core components:
Income: The total gross rent collected from tenants.
Operating Expenses: Costs required to run the property, including taxes, insurance, management fees, maintenance reserves, and vacancy allowances.
Debt Service: The monthly principal and interest payment to the lender.
Key Metrics Explained
1. Net Operating Income (NOI)
NOI is a critical metric calculated by subtracting all operating expenses from the total revenue. Note: NOI does not include mortgage payments. It measures the profitability of the property itself, independent of financing.
Formula: Gross Income – Operating Expenses = NOI
2. Cap Rate (Capitalization Rate)
The Cap Rate helps you compare the return on investment (ROI) of different properties as if you bought them with all cash. It essentially measures the yield of the property in one year.
Formula: (NOI / Purchase Price) * 100
3. Cash on Cash Return (CoC)
This is arguably the most important metric for investors using leverage (loans). It calculates the annual cash income earned on the actual cash invested (Down Payment + Closing Costs). A CoC of 8-12% is generally considered a solid return in many markets.
Formula: (Annual Cash Flow / Total Cash Invested) * 100
Why Include Vacancy and Maintenance?
Novice investors often make the mistake of calculating returns based solely on Rent minus Mortgage. This calculator forces you to account for "silent killers" of cash flow:
Vacancy Rate: You won't have a tenant 100% of the time. Setting aside 5-8% of rent ensures you are prepared for turnover.
Maintenance & CapEx: Roofs leak and toilets break. Allocating 5-10% of monthly rent ensures you have the funds when repairs are needed.
function calculateRental() {
// 1. Get Input Values
var purchasePrice = parseFloat(document.getElementById('purchasePrice').value) || 0;
var downPaymentPercent = parseFloat(document.getElementById('downPaymentPercent').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var loanTerm = parseFloat(document.getElementById('loanTerm').value) || 0;
var rentalIncome = parseFloat(document.getElementById('rentalIncome').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var propertyTax = parseFloat(document.getElementById('propertyTax').value) || 0;
var insurance = parseFloat(document.getElementById('insurance').value) || 0;
var maintenancePercent = parseFloat(document.getElementById('maintenance').value) || 0;
var managementFeePercent = parseFloat(document.getElementById('managementFee').value) || 0;
var hoaFees = parseFloat(document.getElementById('hoaFees').value) || 0;
var closingCosts = parseFloat(document.getElementById('closingCosts').value) || 0;
// 2. Loan Calculations
var downPaymentAmount = purchasePrice * (downPaymentPercent / 100);
var loanAmount = purchasePrice – downPaymentAmount;
var monthlyInterestRate = (interestRate / 100) / 12;
var numberOfPayments = loanTerm * 12;
var monthlyMortgage = 0;
if (interestRate > 0 && loanTerm > 0) {
monthlyMortgage = (loanAmount * monthlyInterestRate) / (1 – Math.pow(1 + monthlyInterestRate, -numberOfPayments));
}
// 3. Expense Calculations
var monthlyVacancyCost = rentalIncome * (vacancyRate / 100);
var monthlyMaintenanceCost = rentalIncome * (maintenancePercent / 100);
var monthlyManagementCost = rentalIncome * (managementFeePercent / 100);
var monthlyTax = propertyTax / 12;
var monthlyInsurance = insurance / 12;
// Total Operating Expenses (OpEx) – Excluding Mortgage
var monthlyOpEx = monthlyTax + monthlyInsurance + hoaFees + monthlyVacancyCost + monthlyMaintenanceCost + monthlyManagementCost;
// Total Expenses (OpEx + Mortgage)
var totalMonthlyExpenses = monthlyOpEx + monthlyMortgage;
// 4. Profitability Metrics
var monthlyCashFlow = rentalIncome – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// NOI (Annual)
var annualNOI = (rentalIncome * 12) – (monthlyOpEx * 12);
// Cap Rate
var capRate = 0;
if (purchasePrice > 0) {
capRate = (annualNOI / purchasePrice) * 100;
}
// Cash on Cash Return
var totalCashInvested = downPaymentAmount + closingCosts;
var cashOnCash = 0;
if (totalCashInvested > 0) {
cashOnCash = (annualCashFlow / totalCashInvested) * 100;
}
// 5. Update UI
document.getElementById('resultMortgage').innerText = formatCurrency(monthlyMortgage);
document.getElementById('resultExpenses').innerText = formatCurrency(totalMonthlyExpenses);
document.getElementById('resultNOI').innerText = formatCurrency(annualNOI);
document.getElementById('resultCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resultCoC').innerText = cashOnCash.toFixed(2) + "%";
var cfElement = document.getElementById('resultCashFlow');
cfElement.innerText = formatCurrency(monthlyCashFlow);
// Styling for positive/negative cashflow
if (monthlyCashFlow >= 0) {
cfElement.classList.remove('rpc-negative');
cfElement.classList.add('rpc-highlight');
} else {
cfElement.classList.remove('rpc-highlight');
cfElement.classList.add('rpc-negative');
}
// Show results container
document.getElementById('rpcResults').style.display = 'block';
}
function formatCurrency(num) {
return "$" + num.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
}