.rc-row { display: flex; flex-wrap: wrap; margin: 0 -10px; }
.rc-col { flex: 1; min-width: 250px; padding: 0 10px; margin-bottom: 15px; }
.rc-input-group { margin-bottom: 15px; }
.rc-label { display: block; font-weight: 600; margin-bottom: 5px; color: #333; font-size: 14px; }
.rc-input { width: 100%; padding: 10px; border: 1px solid #ddd; border-radius: 4px; font-size: 16px; box-sizing: border-box; }
.rc-input:focus { border-color: #0073aa; outline: none; }
.rc-btn { background-color: #0073aa; color: white; border: none; padding: 12px 24px; font-size: 16px; font-weight: bold; cursor: pointer; border-radius: 4px; width: 100%; transition: background 0.3s; }
.rc-btn:hover { background-color: #005177; }
.rc-results { background-color: #fff; padding: 20px; border-radius: 6px; border: 1px solid #eee; margin-top: 20px; display: none; }
.rc-result-row { display: flex; justify-content: space-between; border-bottom: 1px solid #eee; padding: 10px 0; }
.rc-result-row:last-child { border-bottom: none; }
.rc-result-label { color: #555; }
.rc-result-value { font-weight: 800; color: #222; }
.rc-highlight { color: #28a745; }
.rc-negative { color: #dc3545; }
.rc-h2 { margin-top: 30px; font-size: 24px; color: #333; }
.rc-p { line-height: 1.6; color: #555; margin-bottom: 15px; }
Monthly Financial Analysis
Gross Monthly Income:
$0.00
Monthly Mortgage Payment:
$0.00
Total Monthly Expenses (Operating):
$0.00
NET MONTHLY CASH FLOW:
$0.00
Annual Returns
Annual Net Operating Income (NOI):
$0.00
Cap Rate:
0.00%
Cash on Cash Return (ROI):
0.00%
Understanding Rental Property Cash Flow
Successful real estate investing hinges on the ability to accurately predict cash flow. Cash flow is the net amount of money moving in and out of a rental property business. For investors, positive cash flow means the property's income exceeds its expenses and debt service, providing passive income.
Key Metrics Explained
Net Operating Income (NOI): This is your annual income minus operating expenses (taxes, insurance, maintenance, vacancy) but excluding mortgage payments. It represents the inherent profitability of the property asset itself.
Cap Rate (Capitalization Rate): Calculated as NOI / Purchase Price. This metric helps compare the profitability of different real estate investments regardless of how they are financed.
Cash on Cash Return (CoC): This is the most critical metric for financing investors. It measures the annual cash income earned on the cash actually invested (Down Payment + Closing Costs). Calculated as Annual Cash Flow / Total Cash Invested.
The 1% Rule
A common "rule of thumb" in real estate is the 1% rule, which states that the monthly rent should be at least 1% of the purchase price. While this calculator provides a detailed breakdown, the 1% rule can serve as a quick filter when scanning listings.
function calculateCashFlow() {
// Get Input Values
var price = parseFloat(document.getElementById('propPrice').value) || 0;
var down = parseFloat(document.getElementById('downPayment').value) || 0;
var rate = parseFloat(document.getElementById('interestRate').value) || 0;
var years = parseFloat(document.getElementById('loanTerm').value) || 0;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var tax = parseFloat(document.getElementById('propertyTax').value) || 0;
var insurance = parseFloat(document.getElementById('insurance').value) || 0;
var maint = parseFloat(document.getElementById('maintenance').value) || 0;
var vacancyPercent = parseFloat(document.getElementById('vacancyRate').value) || 0;
// 1. Calculate Mortgage Payment
var loanAmount = price – down;
var monthlyRate = (rate / 100) / 12;
var numPayments = years * 12;
var mortgagePayment = 0;
if (rate === 0) {
mortgagePayment = loanAmount / numPayments;
} else {
mortgagePayment = (loanAmount * monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
}
if (isNaN(mortgagePayment)) mortgagePayment = 0;
// 2. Calculate Monthly Operating Expenses
var monthlyTax = tax / 12;
var monthlyIns = insurance / 12;
var monthlyMaint = maint / 12;
// Vacancy Loss calculation
var vacancyLoss = rent * (vacancyPercent / 100);
var effectiveGrossIncome = rent – vacancyLoss;
var totalMonthlyExpenses = monthlyTax + monthlyIns + monthlyMaint; // Operating expenses only (not mortgage)
// 3. Calculate Metrics
var monthlyNOI = effectiveGrossIncome – totalMonthlyExpenses;
var monthlyCashFlow = monthlyNOI – mortgagePayment;
var annualNOI = monthlyNOI * 12;
var annualCashFlow = monthlyCashFlow * 12;
// Cap Rate = Annual NOI / Purchase Price
var capRate = (price > 0) ? (annualNOI / price) * 100 : 0;
// Cash on Cash = Annual Cash Flow / Cash Invested (Down Payment)
// Note: In a real scenario, we would add closing costs to the denominator.
var cocReturn = (down > 0) ? (annualCashFlow / down) * 100 : 0;
// 4. Update UI
document.getElementById('resultsArea').style.display = 'block';
// Helper to format currency
var fmt = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
document.getElementById('resGrossIncome').innerText = fmt.format(effectiveGrossIncome);
document.getElementById('resMortgage').innerText = fmt.format(mortgagePayment);
document.getElementById('resExpenses').innerText = fmt.format(totalMonthlyExpenses);
var cfElement = document.getElementById('resCashFlow');
cfElement.innerText = fmt.format(monthlyCashFlow);
if(monthlyCashFlow >= 0) {
cfElement.style.color = "#28a745";
} else {
cfElement.style.color = "#dc3545";
}
document.getElementById('resNOI').innerText = fmt.format(annualNOI);
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
var cocElement = document.getElementById('resCoC');
cocElement.innerText = cocReturn.toFixed(2) + "%";
if(cocReturn >= 0) {
cocElement.style.color = "#222";
} else {
cocElement.style.color = "#dc3545";
}
}