Analyze the potential profitability of your real estate investment.
Monthly Financial Analysis
Gross Rental Income (Adjusted for Vacancy):$0.00
Total Monthly Expenses:$0.00
Mortgage Payment (P&I):$0.00
Net Monthly Cash Flow:$0.00
Annual Returns
Net Operating Income (NOI):$0.00
Cash on Cash Return:0.00%
Cap Rate:0.00%
function calculateCashFlow() {
// Get Inputs
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var downPercent = parseFloat(document.getElementById('downPayment').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var loanTerm = parseFloat(document.getElementById('loanTerm').value) || 0;
var monthlyRent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var annualTax = parseFloat(document.getElementById('propertyTax').value) || 0;
var annualInsurance = parseFloat(document.getElementById('insurance').value) || 0;
var maintenancePercent = parseFloat(document.getElementById('maintenance').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('hoaFees').value) || 0;
// Loan Calculations
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (interestRate / 100) / 12;
var totalPayments = loanTerm * 12;
var monthlyMortgage = 0;
if (interestRate > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, totalPayments)) / (Math.pow(1 + monthlyRate, totalPayments) – 1);
} else {
monthlyMortgage = loanAmount / totalPayments;
}
if (isNaN(monthlyMortgage)) monthlyMortgage = 0;
// Income Calculations
var vacancyLoss = monthlyRent * (vacancyRate / 100);
var effectiveGrossIncome = monthlyRent – vacancyLoss;
// Expense Calculations (Monthly)
var monthlyTax = annualTax / 12;
var monthlyInsurance = annualInsurance / 12;
var monthlyMaintenance = monthlyRent * (maintenancePercent / 100);
var totalOperatingExpenses = monthlyTax + monthlyInsurance + monthlyMaintenance + monthlyHOA;
var totalMonthlyExpenses = totalOperatingExpenses + monthlyMortgage;
// Profitability Calculations
var monthlyCashFlow = effectiveGrossIncome – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// NOI (Net Operating Income) = Income – Operating Expenses (Excluding Mortgage)
var annualNOI = (effectiveGrossIncome * 12) – (totalOperatingExpenses * 12);
// Cash on Cash Return = Annual Cash Flow / Total Cash Invested (assuming Closing costs ~ 3% of price for estimation + Down Payment)
// For simplicity in this tool, we will use Down Payment as the primary basis, but add a 2% estimated closing cost buffer for realism
var closingCosts = price * 0.02;
var totalCashInvested = downPaymentAmount + closingCosts;
var cashOnCash = 0;
if (totalCashInvested > 0) {
cashOnCash = (annualCashFlow / totalCashInvested) * 100;
}
// Cap Rate = NOI / Purchase Price
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// Display Results
var currencyFormatter = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
document.getElementById('displayGrossIncome').innerText = currencyFormatter.format(effectiveGrossIncome);
document.getElementById('displayTotalExpenses').innerText = currencyFormatter.format(totalMonthlyExpenses);
document.getElementById('displayMortgage').innerText = currencyFormatter.format(monthlyMortgage);
var cashFlowEl = document.getElementById('displayCashFlow');
cashFlowEl.innerText = currencyFormatter.format(monthlyCashFlow);
// Color coding for cash flow
if (monthlyCashFlow >= 0) {
cashFlowEl.className = "result-value positive-flow";
} else {
cashFlowEl.className = "result-value negative-flow";
}
document.getElementById('displayNOI').innerText = currencyFormatter.format(annualNOI);
document.getElementById('displayCoC').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('displayCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('results').style.display = 'block';
}
Understanding Rental Property Cash Flow
Calculating cash flow is the most critical step in evaluating a real estate investment. Cash flow represents the money left over after all expenses, including your mortgage, taxes, insurance, and maintenance, are paid from the monthly rental income. A positive cash flow ensures the property pays for itself and generates passive income, while negative cash flow implies a monthly loss.
How to Use This Calculator
This tool is designed to provide a comprehensive analysis of a potential rental property. To get the most accurate results, ensure you research local property tax rates and insurance costs.
Vacancy Rate: No property is occupied 100% of the time. A standard conservative estimate is 5-8% to account for turnover periods.
Maintenance: Setting aside 10-15% of the rental income for repairs is prudent, especially for older properties.
HOA Fees: If the property is in a managed community, do not forget to include monthly association fees.
Key Metrics Explained
Net Operating Income (NOI)
NOI is a calculation used to analyze the profitability of income-generating real estate investments. It equals all revenue from the property, minus all reasonably necessary operating expenses. Note that NOI excludes mortgage payments. It is a pure measure of the property's ability to generate revenue relative to its operating costs.
Cash on Cash Return
While ROI (Return on Investment) looks at the total picture, Cash on Cash Return measures the annual cash income earned on the property against the actual cash invested (down payment + closing costs). This is often considered the most important metric for investors using leverage (loans), as it tells you how hard your specific dollar is working.
Formula: Annual Pre-Tax Cash Flow / Total Cash Invested
Cap Rate (Capitalization Rate)
Cap Rate indicates the rate of return that is expected to be generated on a real estate investment property. It is calculated by dividing the Net Operating Income (NOI) by the property asset value. It is useful for comparing the profitability of different properties without considering how they are financed.
What is a "Good" Cash Flow?
There is no single answer, as it depends on your investment goals. However, many investors aim for the "1% Rule" as a quick filter (monthly rent should be 1% of the purchase price), though this is becoming harder to find in modern markets. A common benchmark for pure cash flow is $100-$300 net profit per door, per month, after all expenses and reserves.