body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
max-width: 800px;
margin: 0 auto;
padding: 20px;
}
.calculator-container {
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
padding: 25px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
margin-bottom: 40px;
}
.calc-header {
text-align: center;
margin-bottom: 25px;
color: #2c3e50;
}
.input-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.input-grid {
grid-template-columns: 1fr;
}
}
.form-group {
margin-bottom: 15px;
}
.form-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 0.9em;
color: #555;
}
.form-group input {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.form-group input:focus {
border-color: #3498db;
outline: none;
}
.section-title {
grid-column: 1 / -1;
font-size: 1.1em;
font-weight: bold;
color: #2c3e50;
margin-top: 10px;
border-bottom: 2px solid #3498db;
padding-bottom: 5px;
margin-bottom: 15px;
}
.btn-calculate {
display: block;
width: 100%;
background-color: #27ae60;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
margin-top: 20px;
transition: background-color 0.3s;
}
.btn-calculate:hover {
background-color: #219150;
}
#results-area {
margin-top: 30px;
background: #fff;
border: 1px solid #ddd;
border-radius: 4px;
padding: 20px;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.result-row:last-child {
border-bottom: none;
}
.result-label {
color: #666;
}
.result-value {
font-weight: bold;
color: #2c3e50;
}
.highlight-result {
background-color: #e8f6f3;
padding: 15px;
border-radius: 4px;
margin-bottom: 15px;
text-align: center;
}
.highlight-result .result-label {
display: block;
font-size: 1.1em;
color: #27ae60;
margin-bottom: 5px;
}
.highlight-result .result-value {
font-size: 2em;
color: #2c3e50;
}
.negative {
color: #e74c3c !important;
}
.article-content h2 {
color: #2c3e50;
margin-top: 30px;
}
.article-content h3 {
color: #34495e;
}
.article-content p {
margin-bottom: 15px;
}
.article-content ul {
margin-bottom: 20px;
}
.article-content li {
margin-bottom: 8px;
}
function calculateCashFlow() {
// Get Inputs
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var term = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var tax = parseFloat(document.getElementById('annualTaxes').value);
var insurance = parseFloat(document.getElementById('annualInsurance').value);
var hoa = parseFloat(document.getElementById('monthlyHOA').value);
var maintPercent = parseFloat(document.getElementById('maintenanceRate').value);
// Validation
if (isNaN(price) || isNaN(downPercent) || isNaN(rate) || isNaN(term) || isNaN(rent)) {
alert("Please enter valid numbers for all fields.");
return;
}
// Mortgage Calculation
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (rate / 100) / 12;
var totalPayments = term * 12;
var mortgagePayment = 0;
if (rate === 0) {
mortgagePayment = loanAmount / totalPayments;
} else {
mortgagePayment = (loanAmount * monthlyRate) / (1 – Math.pow(1 + monthlyRate, -totalPayments));
}
// Expense Calculations
var monthlyTax = tax / 12;
var monthlyIns = insurance / 12;
var monthlyMaint = rent * (maintPercent / 100);
var totalMonthlyFixedExpenses = monthlyTax + monthlyIns + hoa + monthlyMaint;
var totalMonthlyExpenses = mortgagePayment + totalMonthlyFixedExpenses;
// Income & Returns Calculations
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// Net Operating Income (NOI) = Income – Operating Expenses (Excluding Debt Service)
var annualOperatingExpenses = (totalMonthlyFixedExpenses * 12);
var annualNOI = (rent * 12) – annualOperatingExpenses;
// Cash on Cash Return = Annual Cash Flow / Total Cash Invested
// Assuming cash invested is just down payment for simplicity here, could add closing costs logic
var coc = (annualCashFlow / downPaymentAmount) * 100;
// Cap Rate = NOI / Purchase Price
var capRate = (annualNOI / price) * 100;
// Display Results
var cashFlowEl = document.getElementById('res-monthlyCashFlow');
cashFlowEl.innerText = formatCurrency(monthlyCashFlow);
if (monthlyCashFlow < 0) {
cashFlowEl.classList.add('negative');
} else {
cashFlowEl.classList.remove('negative');
}
document.getElementById('res-coc').innerText = coc.toFixed(2) + "%";
document.getElementById('res-capRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('res-noi').innerText = formatCurrency(annualNOI);
document.getElementById('res-mortgage').innerText = formatCurrency(mortgagePayment);
document.getElementById('res-expenses').innerText = formatCurrency(totalMonthlyExpenses);
// Show result box
document.getElementById('results-area').style.display = 'block';
}
function formatCurrency(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
Understanding Your Rental Property Cash Flow
Investing in real estate is a powerful way to build wealth, but the success of a rental property hinges on the numbers. This Rental Property Cash Flow Calculator helps investors analyze potential deals by breaking down income, expenses, and key return on investment (ROI) metrics.
What is Cash Flow in Real Estate?
Cash flow is the net amount of money moving into and out of a business or property. In real estate, it is calculated as:
Cash Flow = Total Monthly Income – Total Monthly Expenses
Positive cash flow means the property generates more money than it costs to own and operate, providing you with passive income. Negative cash flow means the property costs you money every month, which is generally sustainable only if the property appreciates significantly in value over time.
Key Metrics Explained
1. Net Operating Income (NOI)
NOI calculates the profitability of a property before adding in any costs from financing (mortgage) or taxes. It is essential for determining the intrinsic value of the property.
Formula: (Gross Rental Income – Operating Expenses)
2. Cap Rate (Capitalization Rate)
The Cap Rate measures the natural rate of return on the property, independent of how you pay for it (cash vs. loan). It allows you to compare different properties on an even playing field. A higher Cap Rate generally indicates a better annual return, though often with higher risk.
Formula: (NOI / Purchase Price) × 100
3. Cash on Cash Return (CoC)
This is arguably the most important metric for investors using leverage (mortgages). It measures the return on the actual cash you invested (down payment + closing costs), rather than the total property value.
Formula: (Annual Cash Flow / Total Cash Invested) × 100
Operating Expenses You Must Consider
Many new investors make the mistake of only calculating the mortgage payment. To get an accurate picture of cash flow, you must include:
- Vacancy Rate: Properties won't be rented 100% of the time. Budgeting 5-10% of rent for vacancy is prudent.
- Maintenance & Repairs: Roofs leak and toilets break. Setting aside 10-15% of monthly rent ensures you have funds when issues arise.
- Property Management: Even if you manage it yourself, your time has value. Professional management typically costs 8-10% of monthly rent.
- Capital Expenditures (CapEx): Major expenses like replacing a furnace or roof should be budgeted for separately from general maintenance.
Example Scenario
Let's say you purchase a property for $200,000 with a 20% down payment ($40,000). The interest rate is 6.5%.
- Monthly Rent: $2,000
- Mortgage Payment: ~$1,011
- Taxes & Insurance: ~$300
- Reserves (Maint/Vacancy): ~$300
In this scenario, your total expenses are roughly $1,611. Your monthly cash flow would be $389. Over a year, that is $4,668. With a $40,000 investment, your Cash on Cash return is roughly 11.6%, which is generally considered a strong return in the current market.