Rental Property Cash Flow Calculator
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Rental Property Cash Flow Calculator
Financial Analysis
Monthly P&I Mortgage:
$0.00
Total Monthly Expenses:
$0.00
Monthly Cash Flow:
$0.00
Annual Cash Flow:
$0.00
Net Operating Income (NOI):
$0.00
Cap Rate:
0.00%
Cash on Cash ROI:
0.00%
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but simply buying a property doesn't guarantee a profit. Successful investors rely on accurate data to determine if a property will be an asset or a liability. This Rental Property Cash Flow Calculator helps you analyze the profitability of a potential investment by breaking down income, expenses, and financing costs.
How is Cash Flow Calculated?
Cash flow is the net amount of money moving into or out of a rental property business after all expenses are paid. The formula used in this calculator is:
Cash Flow = Gross Rental Income – (Mortgage Payment + Operating Expenses)
If the result is positive, the property puts money in your pocket every month. If it's negative, you are losing money to hold the asset.
Key Metrics Explained
- Net Operating Income (NOI): This is your annual income minus all operating expenses (taxes, insurance, maintenance) but excluding mortgage payments. It measures the raw profitability of the property itself.
- Cap Rate (Capitalization Rate): Calculated as
NOI / Purchase Price. This percentage helps you compare the return of the property against other investments, regardless of how you finance it. A higher Cap Rate generally indicates a better return, though often with higher risk.
- Cash on Cash ROI: This is arguably the most important metric for investors using leverage (loans). It measures the annual cash return relative to the actual cash you invested (down payment + closing costs).
Estimating Expenses
New investors often underestimate expenses. Beyond the obvious mortgage and taxes, ensure you account for:
- Vacancy: Properties won't be rented 365 days a year. A standard safe estimate is 5-8%.
- Maintenance & CapEx: Roofs leak and toilets break. Setting aside 10-15% of monthly rent helps cover these future costs.
- Property Management: If you hire a manager, expect to pay 8-10% of the monthly rent.
How to Use This Calculator
Start by entering the Purchase Price and expected Monthly Rent. Adjust the Down Payment and Interest Rate to reflect current market conditions. Be honest with your expense estimates—specifically the percentage for maintenance and vacancy—to get a realistic view of your potential Cash on Cash Return.
function calculateROI() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var downPct = parseFloat(document.getElementById('downPaymentPct').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var years = parseFloat(document.getElementById('loanTerm').value) || 0;
var annualTax = parseFloat(document.getElementById('annualTax').value) || 0;
var annualIns = parseFloat(document.getElementById('annualInsurance').value) || 0;
var repairVacancyPct = parseFloat(document.getElementById('repairVacancyPct').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('monthlyHOA').value) || 0;
// 2. Calculate Mortgage (P&I)
var downPaymentAmount = price * (downPct / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (interestRate / 100) / 12;
var totalPayments = years * 12;
var monthlyMortgage = 0;
if (interestRate > 0 && years > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, totalPayments)) / (Math.pow(1 + monthlyRate, totalPayments) – 1);
} else if (years > 0) {
monthlyMortgage = loanAmount / totalPayments;
}
// 3. Calculate Monthly Expenses
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var monthlyRepairVacancy = rent * (repairVacancyPct / 100);
var totalMonthlyExpenses = monthlyMortgage + monthlyTax + monthlyIns + monthlyHOA + monthlyRepairVacancy;
var operatingExpensesOnly = monthlyTax + monthlyIns + monthlyHOA + monthlyRepairVacancy; // Excludes Mortgage for NOI
// 4. Calculate Income & Cash Flow
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// 5. Calculate Metrics (NOI, Cap Rate, COC)
var annualNOI = (rent * 12) – (operatingExpensesOnly * 12);
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
var cashInvested = downPaymentAmount; // Simplified (usually includes closing costs)
var cocROI = 0;
if (cashInvested > 0) {
cocROI = (annualCashFlow / cashInvested) * 100;
}
// 6. Formatting Helper
function formatMoney(num) {
return '$' + num.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
}
function formatPct(num) {
return num.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}) + '%';
}
// 7. Update DOM
document.getElementById('displayMortgage').innerHTML = formatMoney(monthlyMortgage);
document.getElementById('displayExpenses').innerHTML = formatMoney(totalMonthlyExpenses);
var cashFlowEl = document.getElementById('displayCashFlow');
cashFlowEl.innerHTML = formatMoney(monthlyCashFlow);
cashFlowEl.className = 'result-value ' + (monthlyCashFlow >= 0 ? 'positive' : 'negative');
var annualCashFlowEl = document.getElementById('displayAnnualCashFlow');
annualCashFlowEl.innerHTML = formatMoney(annualCashFlow);
annualCashFlowEl.className = 'result-value ' + (annualCashFlow >= 0 ? 'positive' : 'negative');
document.getElementById('displayNOI').innerHTML = formatMoney(annualNOI);
document.getElementById('displayCapRate').innerHTML = formatPct(capRate);
var cocEl = document.getElementById('displayCOC');
cocEl.innerHTML = formatPct(cocROI);
cocEl.className = 'result-value ' + (cocROI >= 0 ? 'positive' : 'negative');
}
// Initialize on load
calculateROI();