Rental Property Cash Flow Calculator
/* Calculator Styles */
.rpc-container {
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
background: #ffffff;
border: 1px solid #e0e0e0;
border-radius: 8px;
box-shadow: 0 4px 12px rgba(0,0,0,0.05);
padding: 0;
overflow: hidden;
}
.rpc-header {
background: #2c3e50;
color: white;
padding: 20px;
text-align: center;
}
.rpc-header h2 {
margin: 0;
font-size: 24px;
}
.rpc-body {
padding: 25px;
display: flex;
flex-wrap: wrap;
gap: 30px;
}
.rpc-inputs {
flex: 1;
min-width: 300px;
}
.rpc-results-section {
flex: 1;
min-width: 300px;
background: #f8f9fa;
border-radius: 6px;
padding: 20px;
border: 1px solid #e9ecef;
}
.rpc-group {
margin-bottom: 15px;
}
.rpc-group label {
display: block;
font-weight: 600;
margin-bottom: 5px;
color: #333;
font-size: 14px;
}
.rpc-input-wrapper {
position: relative;
display: flex;
align-items: center;
}
.rpc-input-wrapper input {
width: 100%;
padding: 10px 10px 10px 35px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
transition: border-color 0.3s;
}
.rpc-input-wrapper input:focus {
border-color: #3498db;
outline: none;
}
.rpc-symbol {
position: absolute;
left: 12px;
color: #7f8c8d;
font-weight: bold;
}
.rpc-btn {
width: 100%;
padding: 12px;
background: #27ae60;
color: white;
border: none;
border-radius: 4px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background 0.3s;
margin-top: 10px;
}
.rpc-btn:hover {
background: #219150;
}
.rpc-result-row {
display: flex;
justify-content: space-between;
align-items: center;
padding: 12px 0;
border-bottom: 1px solid #e0e0e0;
}
.rpc-result-row:last-child {
border-bottom: none;
}
.rpc-result-label {
font-size: 15px;
color: #555;
}
.rpc-result-value {
font-size: 18px;
font-weight: bold;
color: #2c3e50;
}
.rpc-highlight {
color: #27ae60;
font-size: 22px;
}
.rpc-highlight-neg {
color: #c0392b;
font-size: 22px;
}
/* Article Styles */
.rpc-article {
max-width: 800px;
margin: 40px auto;
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
padding: 0 15px;
}
.rpc-article h2 {
color: #2c3e50;
border-bottom: 2px solid #3498db;
padding-bottom: 10px;
margin-top: 30px;
}
.rpc-article h3 {
color: #34495e;
margin-top: 25px;
}
.rpc-article p {
margin-bottom: 15px;
}
.rpc-article ul {
background: #f9f9f9;
padding: 20px 40px;
border-radius: 5px;
border-left: 4px solid #3498db;
}
.rpc-article li {
margin-bottom: 10px;
}
@media (max-width: 600px) {
.rpc-body {
flex-direction: column;
}
}
Monthly Mortgage P&I:
$0.00
Total Monthly Costs:
$0.00
Net Monthly Cash Flow:
$0.00
Annual Cash Flow:
$0.00
Cash on Cash ROI:
0.00%
Initial Cash Invested:
$0.00
function calculateCashFlow() {
// 1. Get Values
var price = parseFloat(document.getElementById('rpc-price').value);
var downPercent = parseFloat(document.getElementById('rpc-down-payment').value);
var rate = parseFloat(document.getElementById('rpc-rate').value);
var term = parseFloat(document.getElementById('rpc-term').value);
var rent = parseFloat(document.getElementById('rpc-rent').value);
var opsExpenses = parseFloat(document.getElementById('rpc-expenses').value);
// Validate inputs
if (isNaN(price) || isNaN(downPercent) || isNaN(rate) || isNaN(term) || isNaN(rent) || isNaN(opsExpenses)) {
alert("Please enter valid numbers in all fields.");
return;
}
// 2. Calculate Mortgage (P&I)
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var downPayment = price * (downPercent / 100);
var loanAmount = price – downPayment;
var monthlyRate = (rate / 100) / 12;
var numberOfPayments = term * 12;
var mortgage = 0;
if (rate === 0) {
mortgage = loanAmount / numberOfPayments;
} else {
mortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// 3. Calculate Totals
var totalMonthlyCost = mortgage + opsExpenses;
var monthlyCashFlow = rent – totalMonthlyCost;
var annualCashFlow = monthlyCashFlow * 12;
// 4. Calculate ROI
// Cash on Cash ROI = Annual Pre-Tax Cash Flow / Total Cash Invested
// Assuming 3% closing costs for estimation if not provided, but we will stick to Down Payment for simplicity or add a buffer
var closingCostsEstimate = price * 0.03;
var totalCashInvested = downPayment + closingCostsEstimate;
var cashOnCashRoi = (annualCashFlow / totalCashInvested) * 100;
// 5. Update DOM
document.getElementById('rpc-mortgage-display').innerText = formatCurrency(mortgage);
document.getElementById('rpc-total-cost-display').innerText = formatCurrency(totalMonthlyCost);
var cashFlowEl = document.getElementById('rpc-cashflow-display');
cashFlowEl.innerText = formatCurrency(monthlyCashFlow);
if(monthlyCashFlow >= 0) {
cashFlowEl.className = "rpc-result-value rpc-highlight";
} else {
cashFlowEl.className = "rpc-result-value rpc-highlight-neg";
}
document.getElementById('rpc-annual-cashflow-display').innerText = formatCurrency(annualCashFlow);
document.getElementById('rpc-roi-display').innerText = cashOnCashRoi.toFixed(2) + "%";
document.getElementById('rpc-invested-display').innerText = formatCurrency(totalCashInvested);
}
function formatCurrency(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
// Initialize on load
window.onload = function() {
calculateCashFlow();
};
Understanding Rental Property Cash Flow
Real estate investing is one of the most reliable ways to build wealth, but the difference between a good investment and a financial burden often comes down to one metric: Cash Flow. This calculator helps investors determine if a specific rental property will generate a positive monthly income after all expenses are paid.
What is Positive Cash Flow?
Positive cash flow occurs when a property's gross monthly rental income exceeds the total of all monthly expenses. These expenses include not just the mortgage principal and interest, but also operating costs such as property taxes, insurance, homeowner association (HOA) fees, maintenance reserves, and vacancy allowances.
For example, if you collect $2,200 in rent and your total mortgage plus expenses equal $1,800, your property generates $400 in positive cash flow every month.
Key Metrics in This Calculator
- Net Monthly Cash Flow: The actual profit in your pocket every month. Investors typically look for at least $100-$300 per door depending on the market.
- Cash on Cash ROI: This measures the return on the actual cash you invested (down payment + closing costs), rather than the total purchase price. It is calculated as: (Annual Cash Flow / Total Cash Invested) × 100. A good benchmark for Cash on Cash return is often considered to be 8-12% or higher.
- Total Cash Invested: This calculator estimates closing costs at 3% of the purchase price added to your down payment to give a realistic view of the capital required to close the deal.
Why Cash Flow Matters More Than Appreciation
While property appreciation (the increase in property value over time) builds long-term equity, cash flow keeps your business running today. Properties with negative cash flow require you to pay out of pocket to keep them afloat, which limits your ability to scale your portfolio. By focusing on the numbers provided by this Rental Property Cash Flow Calculator, you can ensure your investment is self-sustaining and profitable from day one.