Rental Property Cash Flow Calculator
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Cash Flow Analysis
Cash on Cash Return
0.00%
Monthly Expenses Breakdown
Mortgage (P&I):
$0.00
Property Tax:
$0.00
Insurance:
$0.00
HOA Fees:
$0.00
Maintenance (Est):
$0.00
Vacancy (Est):
$0.00
Total Monthly Expenses:
$0.00
Investment Overview
Net Operating Income (Annual):
$0.00
Total Cash Invested:
$0.00
Cap Rate:
0.00%
Rental Property Cash Flow Calculator Guide
Understanding the numbers behind a rental property is the difference between a profitable investment and a financial burden. This Rental Property Cash Flow Calculator helps real estate investors analyze the potential profitability of a purchase by breaking down income, operating expenses, and financing costs.
What is Positive Cash Flow?
Positive cash flow occurs when a property's gross monthly rental income exceeds all combined expenses (mortgage, taxes, insurance, and maintenance). It essentially means the property pays for itself and provides you with passive income every month.
Formula: Cash Flow = Total Income – Total Expenses
Key Metrics Explained
1. Net Operating Income (NOI)
NOI is a critical metric used to determine the profitability of a real estate investment before financing is considered. It is calculated by subtracting all operating expenses from the revenue generated by the property. Note that NOI does not include the mortgage principal and interest payments.
2. Cash on Cash Return (CoC)
This is arguably the most important metric for investors using leverage (loans). It measures the annual cash income earned on the property relative to the amount of cash actually invested (down payment + closing costs + rehab costs).
- 8-12%: Generally considered a solid return in most markets.
- 15%+: Considered an excellent return, often found in high-risk or low-cost markets.
3. Cap Rate (Capitalization Rate)
Cap rate measures the natural rate of return on the investment property assuming it was bought entirely with cash. It is useful for comparing the relative value of different properties regardless of how they are financed.
How to Estimate Expenses Properly
Novice investors often overestimate cash flow by forgetting hidden costs. Our calculator accounts for these crucial factors:
- Vacancy Rate: Properties won't be rented 365 days a year. A standard 5-8% vacancy buffer is recommended.
- Maintenance: Even new homes break. Setting aside 5-10% of rent for repairs ensures you aren't caught off guard when a water heater fails.
- Property Management: If you don't plan to act as the landlord, deduct another 8-10% for management fees (adjust the 'Maintenance' field or subtract from Rent manually if applicable).
Using the Calculator
Enter your purchase price and financing details in the top section. Be realistic with your rental estimates; check local comparables (comps) on Zillow or Rentometer. The calculator will automatically account for monthly breakdown of P&I, taxes, and estimated operational costs to give you the bottom-line "Cash on Cash Return."
function calculateCashFlow() {
// 1. Get Input Values
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 years = parseFloat(document.getElementById('loanTerm').value) || 0;
var closingCosts = parseFloat(document.getElementById('closingCosts').value) || 0;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var taxYearly = parseFloat(document.getElementById('annualTax').value) || 0;
var insYearly = parseFloat(document.getElementById('annualInsurance').value) || 0;
var hoaMonthly = parseFloat(document.getElementById('monthlyHOA').value) || 0;
var maintPercent = parseFloat(document.getElementById('maintenance').value) || 0;
var vacancyPercent = parseFloat(document.getElementById('vacancy').value) || 0;
// 2. Calculate Loan Details
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = years * 12;
// Mortgage P&I Calculation
var monthlyMortgage = 0;
if (interestRate > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
monthlyMortgage = loanAmount / numberOfPayments;
}
if (!isFinite(monthlyMortgage)) monthlyMortgage = 0;
// 3. Calculate Monthly Expenses
var monthlyTax = taxYearly / 12;
var monthlyIns = insYearly / 12;
var monthlyMaint = rent * (maintPercent / 100);
var monthlyVacancy = rent * (vacancyPercent / 100);
var totalOperatingExpenses = monthlyTax + monthlyIns + hoaMonthly + monthlyMaint + monthlyVacancy;
var totalMonthlyExpenses = totalOperatingExpenses + monthlyMortgage;
// 4. Calculate Key Metrics
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
var totalInvested = downPaymentAmount + closingCosts;
// Annual NOI (Rent – Operating Expenses, excludes Mortgage)
var annualNOI = (rent * 12) – (totalOperatingExpenses * 12);
var cashOnCash = 0;
if (totalInvested > 0) {
cashOnCash = (annualCashFlow / totalInvested) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// 5. Update HTML Output
// Helper function for currency formatting
function formatCurrency(num) {
return '$' + num.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
}
function formatPercent(num) {
return num.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}) + '%';
}
document.getElementById('monthlyCashFlowDisplay').innerHTML = formatCurrency(monthlyCashFlow);
document.getElementById('monthlyCashFlowDisplay').style.color = monthlyCashFlow >= 0 ? '#27ae60' : '#c0392b';
document.getElementById('cocReturnDisplay').innerHTML = formatPercent(cashOnCash);
document.getElementById('cocReturnDisplay').style.color = cashOnCash >= 0 ? '#2980b9' : '#c0392b';
document.getElementById('mortgagePayment').innerHTML = formatCurrency(monthlyMortgage);
document.getElementById('taxDisplay').innerHTML = formatCurrency(monthlyTax);
document.getElementById('insuranceDisplay').innerHTML = formatCurrency(monthlyIns);
document.getElementById('hoaDisplay').innerHTML = formatCurrency(hoaMonthly);
document.getElementById('maintDisplay').innerHTML = formatCurrency(monthlyMaint);
document.getElementById('vacancyDisplay').innerHTML = formatCurrency(monthlyVacancy);
document.getElementById('totalExpensesDisplay').innerHTML = formatCurrency(totalMonthlyExpenses);
document.getElementById('noiDisplay').innerHTML = formatCurrency(annualNOI);
document.getElementById('totalInvestedDisplay').innerHTML = formatCurrency(totalInvested);
document.getElementById('capRateDisplay').innerHTML = formatPercent(capRate);
}
// Run calculation on load with default values
window.onload = function() {
calculateCashFlow();
};