.rp-calculator-wrapper {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
padding: 20px;
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
}
.rp-calc-header {
text-align: center;
margin-bottom: 25px;
}
.rp-calc-header h2 {
margin: 0;
color: #2c3e50;
font-size: 24px;
}
.rp-input-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.rp-input-grid {
grid-template-columns: 1fr;
}
}
.rp-input-group {
margin-bottom: 15px;
}
.rp-input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #555;
font-size: 14px;
}
.rp-input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.rp-input-group input:focus {
border-color: #2980b9;
outline: none;
}
.rp-calc-btn {
width: 100%;
padding: 12px;
background-color: #27ae60;
color: white;
border: none;
border-radius: 4px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
margin-top: 10px;
transition: background 0.3s;
}
.rp-calc-btn:hover {
background-color: #219150;
}
.rp-results {
margin-top: 30px;
background: #fff;
padding: 20px;
border-radius: 6px;
border-left: 5px solid #27ae60;
box-shadow: 0 2px 5px rgba(0,0,0,0.05);
display: none;
}
.rp-results h3 {
margin-top: 0;
color: #2c3e50;
border-bottom: 1px solid #eee;
padding-bottom: 10px;
}
.rp-result-row {
display: flex;
justify-content: space-between;
padding: 12px 0;
border-bottom: 1px solid #f0f0f0;
font-size: 16px;
}
.rp-result-row:last-child {
border-bottom: none;
}
.rp-result-label {
color: #7f8c8d;
}
.rp-result-value {
font-weight: bold;
color: #2c3e50;
}
.rp-highlight {
color: #27ae60;
font-size: 1.1em;
}
.rp-negative {
color: #e74c3c;
}
.rp-article {
margin-top: 50px;
line-height: 1.6;
color: #444;
}
.rp-article h2 {
color: #2c3e50;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
margin-top: 30px;
}
.rp-article h3 {
color: #34495e;
margin-top: 25px;
}
.rp-article p {
margin-bottom: 15px;
}
.rp-article ul {
margin-bottom: 15px;
padding-left: 20px;
}
.rp-article li {
margin-bottom: 8px;
}
Investment Analysis
Monthly Mortgage Payment:
$0.00
Total Monthly Expenses (incl. Mortgage):
$0.00
Net Operating Income (Annual):
$0.00
Cap Rate:
0.00%
Cash on Cash Return:
0.00%
Estimated Monthly Cash Flow:
$0.00
function calculateCashFlow() {
// Get inputs
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPct = 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 vacancy = parseFloat(document.getElementById('vacancyRate').value);
var expenses = parseFloat(document.getElementById('monthlyExpenses').value);
// Validation
if (isNaN(price) || isNaN(downPct) || isNaN(rate) || isNaN(term) || isNaN(rent) || isNaN(vacancy) || isNaN(expenses)) {
alert("Please fill in all fields with valid numbers.");
return;
}
// Loan Calculations
var downAmount = price * (downPct / 100);
var loanAmount = price – downAmount;
var monthlyRate = (rate / 100) / 12;
var numPayments = term * 12;
var mortgagePayment = 0;
if (rate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
} else {
mortgagePayment = loanAmount / numPayments;
}
// Income Calculations
var effectiveRent = rent * (1 – (vacancy / 100));
// Expense Calculations
var totalMonthlyExpenses = expenses + mortgagePayment;
// Profit Calculations
var monthlyCashFlow = effectiveRent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// NOI (Net Operating Income) = (Income – Operating Expenses) * 12. Excludes mortgage.
// Operating expenses here is just the 'expenses' input, mortgage is debt service.
var annualNOI = (effectiveRent – expenses) * 12;
// ROI Metrics
// Cap Rate = Annual NOI / Purchase Price
var capRate = (annualNOI / price) * 100;
// Cash on Cash = Annual Cash Flow / Total Cash Invested (Down payment)
// Note: In a real scenario, closing costs would be added to downAmount. We use downAmount for simplicity here.
var cashInvested = downAmount;
var cocReturn = 0;
if (cashInvested > 0) {
cocReturn = (annualCashFlow / cashInvested) * 100;
}
// Formatting Output
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
});
document.getElementById('resMortgage').innerText = formatter.format(mortgagePayment);
document.getElementById('resTotalExp').innerText = formatter.format(totalMonthlyExpenses);
document.getElementById('resNOI').innerText = formatter.format(annualNOI);
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resCoC').innerText = cocReturn.toFixed(2) + "%";
var cashFlowEl = document.getElementById('resCashFlow');
cashFlowEl.innerText = formatter.format(monthlyCashFlow);
// Styling for positive/negative cash flow
if (monthlyCashFlow >= 0) {
cashFlowEl.className = "rp-result-value rp-highlight";
cashFlowEl.style.color = "#27ae60";
} else {
cashFlowEl.className = "rp-result-value rp-negative";
cashFlowEl.style.color = "#e74c3c";
}
// Show results
document.getElementById('resultsSection').style.display = 'block';
}
How to Analyze Rental Property Profitability
Investing in real estate is one of the most reliable ways to build wealth, but simply buying a property and renting it out doesn't guarantee a profit. To succeed, investors must rigorously analyze the numbers before signing a contract. This Rental Property Cash Flow Calculator helps you evaluate the potential return on investment (ROI) by accounting for income, expenses, and debt service.
Key Real Estate Investment Metrics Explained
Understanding these three core metrics is essential for any real estate investor:
1. Cash Flow
Cash flow is the net amount of money moving in or out of your business (property) monthly. It is calculated by subtracting your total monthly expenses (mortgage, taxes, insurance, repairs) from your effective rental income. Positive cash flow means the property pays for itself and generates profit; negative cash flow means you are losing money every month.
2. Cap Rate (Capitalization Rate)
The Cap Rate measures the natural rate of return of a property assuming it was bought with cash. It is calculated as Net Operating Income (NOI) / Purchase Price. It helps compare the profitability of different properties regardless of how they are financed. A higher cap rate generally implies a better return but may come with higher risk.
3. Cash on Cash Return (CoC)
Cash on Cash return is arguably the most important metric for leveraged investors. It measures the annual cash income earned on the cash you actually invested (your down payment and closing costs). Unlike the Cap Rate, CoC takes your mortgage debt into account. A good CoC return is typically considered to be anywhere from 8% to 12% or higher, depending on the market.
How to Estimate Operating Expenses
A common mistake beginners make is underestimating expenses. When using this calculator, ensure your "Monthly Operating Expenses" field includes:
- Property Taxes: Usually 1% to 2.5% of the property value annually.
- Insurance: Landlord insurance policies.
- HOA Fees: If the property is in a managed community.
- Maintenance & Repairs: Rule of thumb is to budget 1% of the property value per year, or 10-15% of the rent.
- Property Management: typically 8-10% of monthly rent if you hire a professional manager.
Why Vacancy Rate Matters
No property is occupied 100% of the time. Tenants move out, and it takes time to clean, repair, and market the unit. A standard vacancy allowance is 5% to 8% (about 2-4 weeks of vacancy per year). This calculator automatically adjusts your gross rental income to give you a realistic "Effective Rental Income" figure.