:root {
–primary-color: #2c3e50;
–secondary-color: #27ae60;
–accent-color: #ecf0f1;
–text-color: #333;
–border-radius: 8px;
}
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: var(–text-color);
max-width: 1200px;
margin: 0 auto;
padding: 20px;
background-color: #f9f9f9;
}
.calculator-container {
background: #fff;
padding: 30px;
border-radius: var(–border-radius);
box-shadow: 0 4px 6px rgba(0,0,0,0.1);
margin-bottom: 40px;
border: 1px solid #ddd;
}
.calc-header {
text-align: center;
margin-bottom: 25px;
}
.calc-header h2 {
color: var(–primary-color);
margin: 0;
}
.grid-container {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 768px) {
.grid-container {
grid-template-columns: 1fr;
}
}
.section-title {
grid-column: 1 / -1;
font-size: 1.1em;
font-weight: bold;
color: var(–primary-color);
border-bottom: 2px solid var(–accent-color);
padding-bottom: 5px;
margin-top: 10px;
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 500;
font-size: 0.9em;
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus {
border-color: var(–secondary-color);
outline: none;
}
.btn-container {
grid-column: 1 / -1;
text-align: center;
margin-top: 20px;
}
button.calc-btn {
background-color: var(–secondary-color);
color: white;
border: none;
padding: 15px 40px;
font-size: 18px;
border-radius: var(–border-radius);
cursor: pointer;
transition: background 0.3s;
font-weight: bold;
}
button.calc-btn:hover {
background-color: #219150;
}
.results-section {
grid-column: 1 / -1;
background-color: var(–accent-color);
padding: 20px;
border-radius: var(–border-radius);
margin-top: 20px;
display: none;
}
.result-grid {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
gap: 15px;
}
.result-item {
background: #fff;
padding: 15px;
border-radius: 6px;
text-align: center;
box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.result-label {
display: block;
font-size: 0.85em;
color: #666;
margin-bottom: 5px;
}
.result-value {
font-size: 1.4em;
font-weight: bold;
color: var(–primary-color);
}
.positive { color: var(–secondary-color); }
.negative { color: #c0392b; }
/* Article Styles */
.content-article {
background: #fff;
padding: 40px;
border-radius: var(–border-radius);
box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.content-article h1 {
color: var(–primary-color);
font-size: 2.5em;
margin-bottom: 0.5em;
}
.content-article h2 {
color: var(–primary-color);
border-bottom: 1px solid #eee;
padding-bottom: 10px;
margin-top: 30px;
}
.content-article p {
margin-bottom: 1.5em;
color: #555;
}
.content-article ul {
margin-bottom: 1.5em;
padding-left: 20px;
}
.content-article li {
margin-bottom: 10px;
}
.highlight-box {
background-color: #e8f6f3;
border-left: 4px solid var(–secondary-color);
padding: 15px;
margin: 20px 0;
}
Understanding Rental Property Analysis
Investing in real estate is a numbers game. Whether you are looking at a single-family home, a duplex, or a large apartment complex, the difference between a profitable asset and a money pit lies in the analysis. This Rental Property Cash Flow Calculator is designed to help investors accurately predict the financial performance of a potential property.
Pro Tip: Never rely solely on the "1% Rule" (where rent equals 1% of the purchase price). While it's a quick filter, true cash flow depends heavily on expenses like taxes, insurance, and interest rates, which vary by location.
Key Metrics Explained
1. Net Operating Income (NOI)
NOI is the foundation of real estate valuation. It represents the total income the property generates after all operating expenses are paid, but before the mortgage is paid. The formula is:
NOI = (Gross Income - Vacancy) - Operating Expenses
Operating expenses include property management, taxes, insurance, repairs, and HOA fees. Note that mortgage payments are NOT included in NOI calculations.
2. Cash Flow
Cash flow is what ends up in your bank account every month. It determines if the property pays you or if you have to pay the property.
Cash Flow = NOI - Debt Service (Mortgage Payment)
Positive cash flow allows you to weather vacancies and save for future repairs. Negative cash flow is a risk that should generally be avoided unless there is significant appreciation potential.
3. Cash on Cash Return (CoC ROI)
This metric tells you how hard your actual invested cash is working. Unlike Cap Rate, which looks at the property's unleveraged yield, CoC ROI considers financing.
CoC ROI = (Annual Cash Flow / Total Cash Invested) × 100
Total Cash Invested includes your down payment, closing costs, and immediate repair costs. A CoC return of 8-12% is often considered a solid target for residential rentals.
4. Cap Rate (Capitalization Rate)
Cap Rate measures the natural rate of return of the property as if you bought it with all cash. It is useful for comparing the profitability of different properties regardless of how they are financed.
Cap Rate = (Annual NOI / Purchase Price) × 100
Estimating Expenses Correctly
One of the biggest mistakes new investors make is underestimating expenses. Always account for:
- Vacancy: Even in hot markets, tenants move out. Use 5-8% as a standard buffer.
- CapEx (Capital Expenditures): Roofs, HVAC systems, and water heaters eventually break. Setting aside 5-10% of rent monthly ensures you have funds when these big-ticket items fail.
- Management Fees: Even if you self-manage now, analyze the deal as if you were paying a manager (typically 8-10%) to ensure the "deal" isn't just a part-time job.
How to Use This Calculator
Enter the purchase details in Section 1 to determine your loan costs. In Section 2, input your expected rental income and a vacancy allowance. Finally, be honest with your expenses in Section 3. The calculator will output your estimated monthly cash flow and return on investment metrics instantly.
function calculateRental() {
// 1. Get Values
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var years = parseFloat(document.getElementById('loanTerm').value) || 0;
var closingCosts = parseFloat(document.getElementById('closingCosts').value) || 0;
var grossRent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var mgmtFeePercent = parseFloat(document.getElementById('managementFee').value) || 0;
var annualTax = parseFloat(document.getElementById('propertyTax').value) || 0;
var annualIns = parseFloat(document.getElementById('insurance').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('hoaFees').value) || 0;
var repairPercent = parseFloat(document.getElementById('repairMaintenance').value) || 0;
var capexPercent = parseFloat(document.getElementById('capex').value) || 0;
// 2. Loan Calculations
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = years * 12;
var monthlyPI = 0;
if (loanAmount > 0 && interestRate > 0) {
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else if (loanAmount > 0) {
monthlyPI = loanAmount / numberOfPayments;
}
// 3. Income Calculations
var vacancyLoss = grossRent * (vacancyRate / 100);
var effectiveGrossIncome = grossRent – vacancyLoss;
// 4. Expense Calculations
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var mgmtFeeAmount = effectiveGrossIncome * (mgmtFeePercent / 100); // Usually on collected rent
var repairAmount = grossRent * (repairPercent / 100);
var capexAmount = grossRent * (capexPercent / 100);
var totalMonthlyOperatingExpenses = monthlyTax + monthlyIns + monthlyHOA + mgmtFeeAmount + repairAmount + capexAmount;
// 5. Analysis Metrics
var monthlyNOI = effectiveGrossIncome – totalMonthlyOperatingExpenses;
var annualNOI = monthlyNOI * 12;
var monthlyCashFlow = monthlyNOI – monthlyPI;
var annualCashFlow = monthlyCashFlow * 12;
var totalCashInvested = downPaymentAmount + closingCosts;
// Avoid division by zero
var cashOnCash = 0;
if (totalCashInvested > 0) {
cashOnCash = (annualCashFlow / totalCashInvested) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
var totalMonthlyExpenses = totalMonthlyOperatingExpenses + monthlyPI;
// 6. Display Results
var fmtMoney = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
var fmtPct = new Intl.NumberFormat('en-US', { style: 'percent', minimumFractionDigits: 2, maximumFractionDigits: 2 });
document.getElementById('resCashFlow').innerHTML = fmtMoney.format(monthlyCashFlow);
document.getElementById('resCashFlow').className = 'result-value ' + (monthlyCashFlow >= 0 ? 'positive' : 'negative');
document.getElementById('resCoc').innerText = fmtPct.format(cashOnCash / 100);
document.getElementById('resCoc').className = 'result-value ' + (cashOnCash >= 0 ? 'positive' : 'negative');
document.getElementById('resCapRate').innerText = fmtPct.format(capRate / 100);
document.getElementById('resMortgage').innerText = fmtMoney.format(monthlyPI);
document.getElementById('resTotalExp').innerText = fmtMoney.format(totalMonthlyExpenses);
document.getElementById('resNOI').innerText = fmtMoney.format(monthlyNOI);
document.getElementById('resultsArea').style.display = 'block';
// Scroll to results on mobile
if(window.innerWidth < 768) {
document.getElementById('resultsArea').scrollIntoView({behavior: 'smooth'});
}
}