.rental-calculator-wrapper {
max-width: 800px;
margin: 0 auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
background: #fff;
padding: 20px;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
.rental-calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
.rental-input-group {
margin-bottom: 15px;
}
.rental-input-group label {
display: block;
font-weight: 600;
margin-bottom: 5px;
color: #333;
font-size: 14px;
}
.rental-input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.rental-input-group input:focus {
border-color: #2c3e50;
outline: none;
}
.rental-calc-btn {
grid-column: 1 / -1;
background-color: #27ae60;
color: white;
padding: 15px;
border: none;
border-radius: 4px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background 0.3s;
margin-top: 10px;
width: 100%;
}
.rental-calc-btn:hover {
background-color: #219150;
}
.rental-results {
margin-top: 30px;
padding: 20px;
background-color: #f8f9fa;
border-radius: 6px;
border-left: 5px solid #27ae60;
display: none;
}
.rental-result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.rental-result-row:last-child {
border-bottom: none;
}
.rental-result-label {
color: #555;
font-weight: 500;
}
.rental-result-value {
font-weight: 700;
color: #2c3e50;
font-size: 18px;
}
.rental-highlight {
color: #27ae60;
font-size: 22px;
}
.rental-negative {
color: #c0392b;
}
.rental-article {
margin-top: 40px;
line-height: 1.6;
color: #444;
}
.rental-article h2 {
color: #2c3e50;
margin-top: 30px;
font-size: 24px;
}
.rental-article h3 {
color: #34495e;
font-size: 20px;
margin-top: 20px;
}
.rental-article ul {
padding-left: 20px;
}
.rental-article li {
margin-bottom: 10px;
}
@media (max-width: 600px) {
.rental-calc-grid {
grid-template-columns: 1fr;
}
}
function calculateRentalProperty() {
// 1. Get Values
var price = parseFloat(document.getElementById('purchasePrice').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var term = parseFloat(document.getElementById('loanTerm').value);
var taxes = parseFloat(document.getElementById('annualTaxes').value);
var insurance = parseFloat(document.getElementById('annualInsurance').value);
var vacancyPercent = parseFloat(document.getElementById('vacancyRate').value);
var maintPercent = parseFloat(document.getElementById('maintenanceRate').value);
var hoa = parseFloat(document.getElementById('hoaFees').value);
// 2. Validation
if (isNaN(price) || isNaN(rent) || isNaN(downPercent) || isNaN(rate) || isNaN(term) || isNaN(taxes)) {
alert("Please enter valid numbers in all fields.");
return;
}
// 3. Core Calculations
// Loan Setup
var downPayment = price * (downPercent / 100);
var loanAmount = price – downPayment;
var closingCosts = price * 0.03; // Estimated 3% closing costs
var totalCashInvested = downPayment + closingCosts;
// Mortgage Calculation
var monthlyRate = rate / 100 / 12;
var numPayments = term * 12;
var monthlyMortgage = 0;
if (rate === 0) {
monthlyMortgage = loanAmount / numPayments;
} else {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
}
// Monthly Expenses
var monthlyTaxes = taxes / 12;
var monthlyInsurance = insurance / 12;
var monthlyVacancy = rent * (vacancyPercent / 100);
var monthlyMaintenance = rent * (maintPercent / 100);
var totalMonthlyExpenses_NoMortgage = monthlyTaxes + monthlyInsurance + monthlyVacancy + monthlyMaintenance + hoa;
var totalMonthlyExpenses = totalMonthlyExpenses_NoMortgage + monthlyMortgage;
// Income Metrics
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// NOI (Net Operating Income) = Income – Operating Expenses (No Mortgage)
var annualNOI = (rent * 12) – (totalMonthlyExpenses_NoMortgage * 12);
// ROI Metrics
var cocReturn = (annualCashFlow / totalCashInvested) * 100;
var capRate = (annualNOI / price) * 100;
// 4. Update UI
document.getElementById('monthlyCashFlowResult').innerHTML = "$" + monthlyCashFlow.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('annualCashFlowResult').innerHTML = "$" + annualCashFlow.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('cocResult').innerHTML = cocReturn.toFixed(2) + "%";
document.getElementById('capRateResult').innerHTML = capRate.toFixed(2) + "%";
document.getElementById('noiResult').innerHTML = "$" + annualNOI.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('mortgageResult').innerHTML = "$" + monthlyMortgage.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('cashToCloseResult').innerHTML = "$" + totalCashInvested.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}) + " (incl. est. 3% closing costs)";
// Styling positive/negative cash flow
var cfElement = document.getElementById('monthlyCashFlowResult');
if(monthlyCashFlow < 0) {
cfElement.style.color = "#c0392b";
} else {
cfElement.style.color = "#27ae60";
}
// Show Results
document.getElementById('rentalResults').style.display = "block";
}
Rental Property Cash Flow Calculator
Analysis Results
Monthly Cash Flow
$0.00
Annual Cash Flow
$0.00
Cash on Cash Return (ROI)
0.00%
Cap Rate
0.00%
Net Operating Income (NOI)
$0.00
Monthly Mortgage Payment
$0.00
Total Cash Needed to Close
$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 profit. The most critical metric for any buy-and-hold investor is Cash Flow. This calculator helps you determine if a specific property will put money in your pocket every month or drain your resources.
What is Cash Flow?
Cash flow is the net amount of money left over after all expenses are paid. It is calculated by subtracting your total monthly expenses (mortgage, taxes, insurance, repairs, vacancy) from your total monthly rental income. A positive cash flow means the property is profitable on a month-to-month basis.
Key Metrics Explained
- Cash on Cash Return (CoC): This measures the annual return on the actual cash you invested (down payment + closing costs). A CoC of 8-12% is generally considered a solid return for real estate investors.
- Cap Rate (Capitalization Rate): This metric evaluates the profitability of a property regardless of how it is financed. It is calculated by dividing the Net Operating Income (NOI) by the purchase price. It helps compare properties purely on their income-generating potential.
- Net Operating Income (NOI): This is your total income minus operating expenses, excluding mortgage payments. Lenders look at this number to determine if the property generates enough income to cover the debt.
The 50% Rule and 1% Rule
When quickly screening properties, investors often use "rules of thumb." The 1% Rule suggests that the monthly rent should be at least 1% of the purchase price (e.g., a $200,000 home should rent for $2,000). The 50% Rule estimates that 50% of your rental income will go toward operating expenses (excluding the mortgage). While useful for quick estimates, our calculator above provides a much more accurate detailed analysis.
Hidden Costs to Watch For
Many new investors fail because they underestimate expenses. Always account for:
- Vacancy: Properties will not be rented 100% of the time. Budgeting 5-8% for vacancy ensures you have reserves during turnover.
- CapEx (Capital Expenditures): Roofs, HVAC systems, and water heaters eventually break. Setting aside 5-10% of rent for these big-ticket items is crucial for long-term solvency.
- Property Management: Even if you self-manage now, your time has value. Factor in 8-10% for management fees so the deal still works if you hire a pro later.