.calc-header { text-align: center; margin-bottom: 30px; }
.calc-header h2 { color: #2c3e50; margin: 0; font-size: 28px; }
.calc-header p { color: #7f8c8d; font-size: 16px; margin-top: 10px; }
.calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
@media (max-width: 600px) { .calc-grid { grid-template-columns: 1fr; } }
.input-group { margin-bottom: 15px; }
.input-group label { display: block; margin-bottom: 5px; color: #34495e; font-weight: 600; font-size: 14px; }
.input-group input { width: 100%; padding: 10px; border: 1px solid #bdc3c7; border-radius: 4px; font-size: 16px; box-sizing: border-box; transition: border 0.3s; }
.input-group input:focus { border-color: #3498db; outline: none; }
.calc-btn-container { text-align: center; margin-top: 20px; grid-column: 1 / -1; }
.calc-btn { background-color: #2ecc71; color: white; border: none; padding: 12px 30px; font-size: 18px; font-weight: bold; border-radius: 5px; cursor: pointer; transition: background 0.3s; }
.calc-btn:hover { background-color: #27ae60; }
.results-section { background: white; padding: 25px; border-radius: 8px; margin-top: 30px; border-left: 5px solid #2ecc71; display: none; }
.results-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.result-item { text-align: center; }
.result-label { font-size: 14px; color: #7f8c8d; text-transform: uppercase; letter-spacing: 1px; }
.result-value { font-size: 24px; color: #2c3e50; font-weight: 700; margin-top: 5px; }
.positive-cf { color: #27ae60; }
.negative-cf { color: #c0392b; }
.article-content { margin-top: 50px; line-height: 1.6; color: #2c3e50; background: #fff; padding: 30px; border-radius: 8px; border: 1px solid #eee; }
.article-content h2 { color: #2c3e50; border-bottom: 2px solid #ecf0f1; padding-bottom: 10px; margin-top: 30px; }
.article-content h3 { color: #34495e; margin-top: 20px; }
.article-content ul { padding-left: 20px; }
.article-content li { margin-bottom: 10px; }
function calculateCashFlow() {
// Get Input Values
var monthlyRent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var otherIncome = parseFloat(document.getElementById('otherIncome').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var propertyPrice = parseFloat(document.getElementById('propertyPrice').value) || 0;
var downPaymentPercent = parseFloat(document.getElementById('downPayment').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var loanTerm = parseFloat(document.getElementById('loanTerm').value) || 0;
var annualTaxes = parseFloat(document.getElementById('annualTaxes').value) || 0;
var annualInsurance = parseFloat(document.getElementById('annualInsurance').value) || 0;
var monthlyHoa = parseFloat(document.getElementById('monthlyHoa').value) || 0;
var maintenanceCosts = parseFloat(document.getElementById('maintenanceCosts').value) || 0;
var managementFeePercent = parseFloat(document.getElementById('propertyManagement').value) || 0;
// 1. Calculate Revenue
var grossMonthlyIncome = monthlyRent + otherIncome;
var vacancyLoss = grossMonthlyIncome * (vacancyRate / 100);
var effectiveGrossIncome = grossMonthlyIncome – vacancyLoss;
// 2. Calculate Mortgage
var downPaymentAmount = propertyPrice * (downPaymentPercent / 100);
var loanAmount = propertyPrice – downPaymentAmount;
var monthlyInterestRate = (interestRate / 100) / 12;
var numberOfPayments = loanTerm * 12;
var monthlyMortgage = 0;
if (loanAmount > 0 && interestRate > 0) {
monthlyMortgage = loanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
} else if (loanAmount > 0 && interestRate === 0) {
monthlyMortgage = loanAmount / numberOfPayments;
}
// 3. Calculate Expenses
var monthlyTaxes = annualTaxes / 12;
var monthlyInsurance = annualInsurance / 12;
var monthlyMaintenance = maintenanceCosts / 12;
var monthlyManagement = effectiveGrossIncome * (managementFeePercent / 100);
var totalMonthlyOperatingExpenses = monthlyTaxes + monthlyInsurance + monthlyHoa + monthlyMaintenance + monthlyManagement;
var totalMonthlyExpenses = totalMonthlyOperatingExpenses + monthlyMortgage;
// 4. Calculate Key Metrics
var monthlyCashFlow = effectiveGrossIncome – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// Net Operating Income (NOI) = Income – Operating Expenses (Excluding Mortgage)
var monthlyNoi = effectiveGrossIncome – totalMonthlyOperatingExpenses;
var annualNoi = monthlyNoi * 12;
// Cash on Cash Return = Annual Cash Flow / Total Cash Invested (Down Payment)
// Note: Simplification excluding closing costs for general use
var cocReturn = 0;
if (downPaymentAmount > 0) {
cocReturn = (annualCashFlow / downPaymentAmount) * 100;
}
// Cap Rate = NOI / Property Price
var capRate = 0;
if (propertyPrice > 0) {
capRate = (annualNoi / propertyPrice) * 100;
}
// Display Results
var cashFlowElement = document.getElementById('monthlyCashFlow');
cashFlowElement.innerText = formatCurrency(monthlyCashFlow);
cashFlowElement.className = monthlyCashFlow >= 0 ? 'result-value positive-cf' : 'result-value negative-cf';
document.getElementById('cocReturn').innerText = cocReturn.toFixed(2) + '%';
document.getElementById('annualNoi').innerText = formatCurrency(annualNoi);
document.getElementById('capRate').innerText = capRate.toFixed(2) + '%';
document.getElementById('totalCashResult').innerText = formatCurrency(downPaymentAmount);
document.getElementById('mortgageResult').innerText = formatCurrency(monthlyMortgage);
// Show results div
document.getElementById('results').style.display = 'block';
}
function formatCurrency(num) {
return '$' + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
Understanding Rental Property Cash Flow
Before investing in real estate, calculating cash flow is the single most critical step to ensuring profitability. Cash flow represents the net amount of money moving in and out of a business—in this case, your rental property—after all expenses have been paid. A positive cash flow means your liquid assets are increasing, providing you with passive income, while a negative cash flow implies the asset is costing you money to hold.
How This Calculator Works
This Rental Property Cash Flow Calculator takes into account all major variables affecting real estate profitability:
- Effective Gross Income: Your total rent and other income minus the expected vacancy rate. Even in hot markets, it is prudent to budget for a 5-8% vacancy rate.
- Operating Expenses: These are the costs required to keep the property running, including property taxes, insurance, HOA fees, maintenance reserves, and property management fees. Note that operating expenses do not include your mortgage payment.
- Net Operating Income (NOI): This is your income minus operating expenses. NOI is crucial for determining the raw profitability of the property irrespective of financing.
- Debt Service: The principal and interest payments on your loan.
Key Metrics Explained
Cash on Cash Return (CoC)
The Cash on Cash return measures the annual return the investor made on the property in relation to the amount of mortgage paid during the same year. It is considered one of the most important ROI metrics in real estate because it looks at the actual cash invested (your down payment) rather than the total loan amount.
Formula: Annual Cash Flow / Total Cash Invested
Cap Rate (Capitalization Rate)
The Cap Rate indicates the rate of return that is expected to be generated on a real estate investment property. It is based on the Net Operating Income (NOI) the property generates. Cap rate is useful for comparing different properties without considering how they are financed (cash vs. mortgage).
Formula: Net Operating Income / Current Market Value
What is a "Good" Cash Flow?
While "good" is subjective, many investors follow the 1% Rule (monthly rent should be 1% of the purchase price) as a quick filter. However, for actual cash flow, most investors aim for:
- $100 – $200 per door per month as a minimum for single-family homes.
- 8% – 12% Cash on Cash Return to outperform the average stock market returns.
Use the calculator above to adjust your offer price, down payment, or rent expectations to see how different scenarios affect your bottom line.