.calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 800px;
margin: 0 auto;
background: #fff;
padding: 20px;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
margin-bottom: 25px;
}
@media (max-width: 600px) {
.calc-grid { grid-template-columns: 1fr; }
}
.input-group {
margin-bottom: 10px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #2c3e50;
font-size: 0.9em;
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus {
border-color: #3498db;
outline: none;
box-shadow: 0 0 5px rgba(52, 152, 219, 0.3);
}
.section-title {
grid-column: 1 / -1;
font-size: 1.1em;
color: #34495e;
border-bottom: 2px solid #eee;
padding-bottom: 5px;
margin-top: 10px;
margin-bottom: 10px;
}
button.calc-btn {
background-color: #27ae60;
color: white;
border: none;
padding: 15px 30px;
font-size: 18px;
border-radius: 5px;
cursor: pointer;
width: 100%;
transition: background 0.3s;
font-weight: bold;
}
button.calc-btn:hover {
background-color: #219150;
}
#results-area {
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 5px;
padding: 20px;
margin-top: 25px;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #e0e0e0;
}
.result-row:last-child {
border-bottom: none;
}
.result-label {
font-weight: 600;
color: #555;
}
.result-value {
font-weight: bold;
color: #2c3e50;
}
.result-highlight {
color: #27ae60;
font-size: 1.2em;
}
.result-negative {
color: #c0392b;
}
.article-content {
margin-top: 40px;
line-height: 1.6;
color: #333;
}
.article-content h2 {
color: #2c3e50;
margin-top: 30px;
}
.article-content h3 {
color: #34495e;
}
.article-content ul {
padding-left: 20px;
}
.article-content li {
margin-bottom: 10px;
}
function calculateRentalROI() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('propPrice').value);
var downPercent = parseFloat(document.getElementById('downPayment').value);
var interestRate = parseFloat(document.getElementById('intRate').value);
var termYears = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var annualTax = parseFloat(document.getElementById('propTax').value);
var annualIns = parseFloat(document.getElementById('homeIns').value);
var monthlyHOA = parseFloat(document.getElementById('hoaFee').value);
var vacancyPercent = parseFloat(document.getElementById('vacancyRate').value);
var capexPercent = parseFloat(document.getElementById('capexRate').value);
var mgmtPercent = parseFloat(document.getElementById('mgmtFee').value);
var closingCosts = parseFloat(document.getElementById('closingCosts').value);
// Validation
if (isNaN(price) || isNaN(rent) || isNaN(interestRate) || isNaN(termYears)) {
alert("Please enter valid numbers for Price, Rent, Interest Rate, and Loan Term.");
return;
}
// 2. Calculate Initial Cash Investment
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var totalCashInvested = downPaymentAmount + closingCosts;
// 3. Calculate Mortgage Payment (Principal & Interest)
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = termYears * 12;
var monthlyPI = 0;
if (interestRate === 0) {
monthlyPI = loanAmount / numberOfPayments;
} else {
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// 4. Calculate Monthly Operating Expenses
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var vacancyCost = rent * (vacancyPercent / 100);
var capexCost = rent * (capexPercent / 100);
var mgmtCost = rent * (mgmtPercent / 100);
var totalMonthlyExpenses = monthlyPI + monthlyTax + monthlyIns + monthlyHOA + vacancyCost + capexCost + mgmtCost;
var operatingExpensesOnly = totalMonthlyExpenses – monthlyPI; // For NOI calculation
// 5. Calculate Metrics
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// NOI = (Gross Income – Operating Expenses (Excluding Debt Service)) * 12 (Assuming annualized)
// Note: NOI is typically Annual
var annualNOI = (rent * 12) – (operatingExpensesOnly * 12);
var capRate = (annualNOI / price) * 100;
var cocReturn = (annualCashFlow / totalCashInvested) * 100;
// 6. Display Results
// Helper for currency formatting
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
document.getElementById('resCashFlow').innerText = formatter.format(monthlyCashFlow);
document.getElementById('resCoc').innerText = cocReturn.toFixed(2) + "%";
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resCashNeeded').innerText = formatter.format(totalCashInvested);
document.getElementById('resMortgage').innerText = formatter.format(monthlyPI);
document.getElementById('resExpenses').innerText = formatter.format(totalMonthlyExpenses);
document.getElementById('resNOI').innerText = formatter.format(annualNOI);
// Styling adjustments based on profitability
var cfElement = document.getElementById('resCashFlow');
if (monthlyCashFlow >= 0) {
cfElement.style.color = "#27ae60";
} else {
cfElement.style.color = "#c0392b";
}
// Show results area
document.getElementById('results-area').style.display = 'block';
}
Rental Property Cash Flow Calculator
Purchase & Loan Details
Income & Expenses
Analysis Results
Monthly Cash Flow:
$0.00
Cash on Cash Return (ROI):
0.00%
Cap Rate:
0.00%
Total Cash Needed:
$0.00
Monthly Mortgage (P&I):
$0.00
Total Monthly Expenses:
$0.00
Net Operating Income (NOI) / Year:
$0.00
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but the difference between a successful investment and a money pit lies in the numbers. This Rental Property Cash Flow Calculator is designed to help investors accurately project the profitability of a potential acquisition by accounting for income, loan costs, and operating expenses.
Why Cash Flow is King
Cash flow represents the net amount of cash moving into or out of your business every month. Positive cash flow means your property generates more income than it costs to operate, providing you with passive income. Negative cash flow implies you must contribute money from your pocket to keep the asset, which increases your risk.
Key Metrics Explained
- NOI (Net Operating Income): This is the annual income generated by the property after deducting all operating expenses (Vacancy, Taxes, Insurance, Repairs, Management) but before deducting mortgage payments. It measures the property's raw profitability.
- Cap Rate (Capitalization Rate): Calculated as
NOI / Purchase Price. This percentage helps you compare the return of a property against other properties, assuming an all-cash purchase. A higher Cap Rate generally indicates a better return but may come with higher risk. - Cash on Cash Return (CoC): This is arguably the most important metric for leveraged investors. It measures the annual cash flow relative to the total cash actually invested (Down Payment + Closing Costs). Formula:
(Annual Cash Flow / Total Cash Invested) * 100.
How to Estimate Expenses
Many new investors underestimate expenses. To get a realistic result from this calculator, ensure you account for:
- Vacancy: Properties don't stay rented 365 days a year. A standard rule of thumb is 5-8% depending on the market.
- CapEx & Repairs: Roofs leak and water heaters break. Setting aside 5-10% of monthly rent ensures you have funds when major repairs are needed.
- Management Fees: Even if you plan to self-manage, it is wise to factor in a 10% management fee to see if the deal still makes sense if you decide to hire a professional later.
Using This Calculator
Enter the purchase details, loan terms, and expected rental income above. Be honest with your expense estimates. The calculator will output your estimated monthly cash flow and your return on investment, helping you make a data-driven decision.