Rental Property Cash Flow Calculator
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Monthly Breakdown
Rental Income:
$0.00
Mortgage Payment (P&I):
$0.00
Property Tax (Monthly):
$0.00
Insurance (Monthly):
$0.00
HOA / Misc:
$0.00
Vacancy & Repairs:
$0.00
Total Monthly Expenses:
$0.00
Investment Metrics
Net Monthly Cash Flow:
$0.00
Annual Cash Flow:
$0.00
Cash on Cash ROI:
0.00%
Cap Rate:
0.00%
Note: "Cash on Cash ROI" is calculated based on the Annual Cash Flow divided by the Down Payment. It does not account for closing costs or renovation costs unless included in the down payment figure.
How to Analyze a Rental Property Investment
Investing in real estate is one of the most reliable ways to build wealth, but it requires careful mathematical analysis. A property might look beautiful, but if the numbers don't work, it becomes a liability rather than an asset. This Rental Property Cash Flow Calculator is designed to help investors determine the viability of a potential purchase by breaking down income, expenses, and return metrics.
Understanding the Key Metrics
When using this calculator, it is crucial to understand what the output figures actually mean for your investment strategy:
- Net Monthly Cash Flow: This is the profit you take home every month after all expenses (mortgage, taxes, insurance, and reserves) are paid. Positive cash flow is essential for long-term sustainability.
- Cash on Cash ROI: This percentage tells you how hard your actual invested cash (down payment) is working. A 10% Cash on Cash ROI means that for every $100 you invested, you are getting $10 back annually in profit.
- Cap Rate (Capitalization Rate): This measures the property's natural rate of return assuming it was bought with cash (no mortgage). It helps compare the profitability of the property itself, excluding the financing method.
Common Expenses Often Overlooked
Many new investors make the mistake of calculating cash flow by simply subtracting the mortgage from the rent. However, true operating expenses include much more:
- Vacancy & Repairs: Houses break, and tenants move out. Successful investors typically set aside 5% to 10% of monthly rent to cover these inevitable costs.
- Property Taxes & Insurance: These can increase annually and must be prorated monthly to get an accurate cash flow picture.
- HOA Fees: If the property is in a managed community, Homeowners Association fees are a mandatory monthly expense that eats directly into profit.
What is a "Good" ROI?
While target returns vary by investor and market, a common benchmark for residential rental properties is a Cash on Cash ROI of 8% to 12%. In highly appreciative markets, investors might accept a lower monthly cash flow (4-6%) in exchange for long-term equity growth. Conversely, in stable markets with lower appreciation, investors often seek higher immediate cash flow (12%+).
Use this calculator to run different scenarios—adjusting the rent, purchase price, or down payment—to find the "sweet spot" where the deal makes financial sense for your portfolio.
function calculateRentalROI() {
// Get Inputs
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPayment = parseFloat(document.getElementById('downPayment').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var term = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var yearlyTax = parseFloat(document.getElementById('annualTax').value);
var yearlyIns = parseFloat(document.getElementById('annualInsurance').value);
var monthlyHOA = parseFloat(document.getElementById('monthlyHOA').value);
var vacancyPercent = parseFloat(document.getElementById('vacancyRate').value);
// Validation
if (isNaN(price) || isNaN(downPayment) || isNaN(rate) || isNaN(term) ||
isNaN(rent) || isNaN(yearlyTax) || isNaN(yearlyIns) || isNaN(monthlyHOA)) {
document.getElementById('errorMsg').style.display = "block";
return;
} else {
document.getElementById('errorMsg').style.display = "none";
}
// Mortgage Calculation
var loanAmount = price – downPayment;
var monthlyRate = rate / 100 / 12;
var numberOfPayments = term * 12;
var monthlyMortgage = 0;
if (monthlyRate > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
monthlyMortgage = loanAmount / numberOfPayments;
}
// Monthly Expenses Calculation
var monthlyTax = yearlyTax / 12;
var monthlyIns = yearlyIns / 12;
var monthlyVacancyRepairs = rent * (vacancyPercent / 100);
var totalMonthlyExpenses = monthlyMortgage + monthlyTax + monthlyIns + monthlyHOA + monthlyVacancyRepairs;
var cashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = cashFlow * 12;
// ROI Metrics
// Cash on Cash ROI = Annual Cash Flow / Total Invested Cash (Using Down Payment as proxy for total cash invested)
var cashOnCash = 0;
if (downPayment > 0) {
cashOnCash = (annualCashFlow / downPayment) * 100;
}
// Cap Rate = Net Operating Income (NOI) / Price
// NOI = (Rent – Operating Expenses (No Mortgage)) * 12
var operatingExpenses = monthlyTax + monthlyIns + monthlyHOA + monthlyVacancyRepairs;
var noiMonthly = rent – operatingExpenses;
var capRate = ((noiMonthly * 12) / price) * 100;
// Formatting Helpers
var currencyFormat = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
// Update DOM
document.getElementById('resIncome').innerText = currencyFormat.format(rent);
document.getElementById('resMortgage').innerText = currencyFormat.format(monthlyMortgage);
document.getElementById('resTax').innerText = currencyFormat.format(monthlyTax);
document.getElementById('resIns').innerText = currencyFormat.format(monthlyIns);
document.getElementById('resHOA').innerText = currencyFormat.format(monthlyHOA);
document.getElementById('resVacancy').innerText = currencyFormat.format(monthlyVacancyRepairs);
document.getElementById('resTotalExp').innerText = currencyFormat.format(totalMonthlyExpenses);
document.getElementById('resCashFlow').innerText = currencyFormat.format(cashFlow);
// Color coding for cash flow
var cashFlowEl = document.getElementById('resCashFlow');
if (cashFlow >= 0) {
cashFlowEl.style.color = "#27ae60";
} else {
cashFlowEl.style.color = "#c0392b";
}
document.getElementById('resAnnualCashFlow').innerText = currencyFormat.format(annualCashFlow);
document.getElementById('resROI').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
}