Rental Property Cash Flow Calculator
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text-align: center;
margin-bottom: 25px;
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.calc-header h2 {
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Purchase Information
Purchase Price ($)
Down Payment (%)
Interest Rate (%)
Loan Term (Years)
Rental Income
Monthly Rent ($)
Vacancy Rate (%)
Monthly Expenses
Annual Property Tax ($)
Annual Insurance ($)
Maintenance & Repairs (%)
HOA / Misc Monthly ($)
Calculate Cash Flow
Monthly Mortgage (P&I):
—
Total Monthly Expenses:
—
Net Operating Income (NOI):
—
Monthly Cash Flow:
—
Cash on Cash Return:
—
Cap Rate:
—
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but the numbers must make sense. This Rental Property Cash Flow Calculator helps investors determine the profitability of a potential purchase by analyzing income, operating expenses, and debt service.
What is Monthly Cash Flow?
Cash flow is the profit you bring in each month after all bills are paid. It is calculated using the formula:
Cash Flow = Total Rental Income – (Operating Expenses + Mortgage Payment)
Positive cash flow means the property pays for itself and puts money in your pocket. Negative cash flow implies you must contribute personal funds to keep the property running, which is generally risky.
Key Metrics Explained
NOI (Net Operating Income): This is your annual income minus operating expenses (like taxes, insurance, and maintenance), but before the mortgage payment. It measures the raw profitability of the asset.Cash on Cash Return (CoC): This metric calculates the cash income earned on the cash invested. It is found by dividing annual pre-tax cash flow by the total cash invested (down payment). A CoC of 8-12% is often considered good in many markets.Cap Rate: The Capitalization Rate indicates the potential return on an investment assuming you paid all cash. It helps compare properties regardless of financing methods.
Example Calculation
Imagine purchasing a property for $250,000 with 20% down ($50,000). If the monthly rent is $2,200 :
Mortgage: At 6.5% interest, your P&I might be ~$1,264.Expenses: Taxes, insurance, vacancy (5%), and maintenance (8%) might total ~$700/month.Result: $2,200 (Income) – $700 (Expenses) – $1,264 (Mortgage) = $236 Monthly Cash Flow .
Using this calculator ensures you account for "hidden" costs like vacancy and maintenance, preventing unexpected losses.
function calculateRental() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('propPrice').value);
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var termYears = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value);
var annualTax = parseFloat(document.getElementById('propertyTax').value);
var annualIns = parseFloat(document.getElementById('homeInsurance').value);
var maintPercent = parseFloat(document.getElementById('maintenancePercent').value);
var hoa = parseFloat(document.getElementById('hoaFees').value);
// Validation: Ensure no NaN inputs
if (isNaN(price) || isNaN(rent) || isNaN(interestRate) || isNaN(termYears)) {
alert("Please enter valid numbers for all fields.");
return;
}
// 2. Perform Calculations
// Loan Calculations
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (interestRate / 100) / 12;
var numPayments = termYears * 12;
var mortgagePayment = 0;
if (interestRate > 0) {
mortgagePayment = (loanAmount * monthlyRate) / (1 – Math.pow(1 + monthlyRate, -numPayments));
} else {
mortgagePayment = loanAmount / numPayments;
}
// Operating Expenses Calculations
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var vacancyCost = rent * (vacancyRate / 100);
var maintenanceCost = rent * (maintPercent / 100);
var totalMonthlyExpenses = monthlyTax + monthlyIns + vacancyCost + maintenanceCost + hoa;
// Net Operating Income (NOI) = Gross Income (adjusted for vacancy) – Operating Expenses
// Note: Gross Income for NOI usually accounts for vacancy loss first.
var effectiveGrossIncome = rent – vacancyCost;
// Operating expenses for NOI usually exclude mortgage but include tax/ins/maint/hoa
var operatingExpensesNOI = monthlyTax + monthlyIns + maintenanceCost + hoa;
var monthlyNOI = effectiveGrossIncome – operatingExpensesNOI;
var annualNOI = monthlyNOI * 12;
// Cash Flow
var monthlyCashFlow = monthlyNOI – mortgagePayment;
var annualCashFlow = monthlyCashFlow * 12;
// ROI Metrics
var totalCashInvested = downPaymentAmount; // Simplified: usually includes closing costs/rehab
var cashOnCash = 0;
if (totalCashInvested > 0) {
cashOnCash = (annualCashFlow / totalCashInvested) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// 3. Formatting Helper
function formatCurrency(num) {
return '$' + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
function formatPercent(num) {
return num.toFixed(2) + '%';
}
// 4. Update UI
document.getElementById('resMortgage').innerText = formatCurrency(mortgagePayment);
// Note: For the UI "Total Monthly Expenses", we typically show Operating Expenses + Vacancy Loss
document.getElementById('resExpenses').innerText = formatCurrency(totalMonthlyExpenses);
document.getElementById('resNOI').innerText = formatCurrency(monthlyNOI);
var cfElement = document.getElementById('resCashFlow');
cfElement.innerText = formatCurrency(monthlyCashFlow);
// Color coding for cash flow
if (monthlyCashFlow >= 0) {
cfElement.className = "positive-cf";
} else {
cfElement.className = "negative-cf";
}
document.getElementById('resCoC').innerText = formatPercent(cashOnCash);
document.getElementById('resCapRate').innerText = formatPercent(capRate);
// Show Results
document.getElementById('resultsArea').style.display = 'block';
}