.calculator-container {
max-width: 800px;
margin: 0 auto;
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
border: 1px solid #e0e0e0;
border-radius: 8px;
background: #ffffff;
box-shadow: 0 4px 10px rgba(0,0,0,0.05);
padding: 20px;
}
.calc-header {
text-align: center;
background-color: #2c3e50;
color: white;
padding: 15px;
border-radius: 8px 8px 0 0;
margin: -20px -20px 20px -20px;
}
.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;
font-weight: 600;
color: #333;
font-size: 0.9em;
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box;
font-size: 1em;
}
.input-group input:focus {
border-color: #27ae60;
outline: none;
}
.section-title {
grid-column: 1 / -1;
font-size: 1.1em;
color: #27ae60;
border-bottom: 2px solid #eee;
padding-bottom: 5px;
margin-top: 10px;
margin-bottom: 10px;
}
.btn-calc {
grid-column: 1 / -1;
background-color: #27ae60;
color: white;
border: none;
padding: 15px;
font-size: 1.1em;
border-radius: 4px;
cursor: pointer;
transition: background 0.3s;
margin-top: 10px;
}
.btn-calc:hover {
background-color: #219150;
}
.results-section {
grid-column: 1 / -1;
background-color: #f9f9f9;
padding: 20px;
border-radius: 4px;
margin-top: 20px;
border-left: 5px solid #27ae60;
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: #555;
font-weight: 500;
}
.result-value {
font-weight: bold;
color: #2c3e50;
}
.result-highlight {
font-size: 1.3em;
color: #27ae60;
}
.calc-content {
margin-top: 40px;
line-height: 1.6;
color: #444;
}
.calc-content h2, .calc-content h3 {
color: #2c3e50;
}
.calc-content ul {
padding-left: 20px;
}
function calculateCashFlow() {
// Get Input 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 rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var yearlyTax = parseFloat(document.getElementById('propertyTax').value) || 0;
var yearlyIns = parseFloat(document.getElementById('insurance').value) || 0;
var maintenanceRate = parseFloat(document.getElementById('maintenance').value) || 0;
var managementRate = parseFloat(document.getElementById('managementFee').value) || 0;
var hoa = parseFloat(document.getElementById('hoaFees').value) || 0;
var closingCosts = parseFloat(document.getElementById('closingCosts').value) || 0;
// 1. Calculate Mortgage
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = years * 12;
var monthlyMortgage = 0;
if (interestRate === 0) {
monthlyMortgage = loanAmount / numberOfPayments;
} else {
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// Handle NaN if years is 0
if (years === 0) monthlyMortgage = 0;
// 2. Calculate Operating Expenses (Monthly)
var vacancyCost = rent * (vacancyRate / 100);
var maintenanceCost = rent * (maintenanceRate / 100);
var managementCost = rent * (managementRate / 100);
var monthlyTax = yearlyTax / 12;
var monthlyIns = yearlyIns / 12;
var totalOperatingExpenses = vacancyCost + maintenanceCost + managementCost + monthlyTax + monthlyIns + hoa;
// 3. Calculate NOI (Net Operating Income)
// NOI = Gross Income – Operating Expenses (Excluding Mortgage)
// Gross Potential Income is Rent. Effective Gross Income is Rent – Vacancy.
// Standard approach: NOI = (Rent – Vacancy) – (OpEx excluding Vacancy)
// Or simply: Rent – (All OpEx).
// Let's stick to standard: Rent – Vacancy – Expenses.
// Adjusted Gross Income
var effectiveGrossIncome = rent – vacancyCost;
// Operating Expenses (Tax, Ins, Maint, Mgmt, HOA)
var operatingExpensesOnly = maintenanceCost + managementCost + monthlyTax + monthlyIns + hoa;
var monthlyNOI = effectiveGrossIncome – operatingExpensesOnly;
var annualNOI = monthlyNOI * 12;
// 4. Calculate Cash Flow
var totalMonthlyExpenses = totalOperatingExpenses + monthlyMortgage;
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// 5. Calculate Returns
var totalCashInvested = downPaymentAmount + closingCosts;
var cashOnCash = 0;
if (totalCashInvested > 0) {
cashOnCash = (annualCashFlow / totalCashInvested) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// Display Results
// Format currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
document.getElementById('resCashFlow').innerText = formatter.format(monthlyCashFlow);
document.getElementById('resNOI').innerText = formatter.format(monthlyNOI);
document.getElementById('resCoC').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resTotalCash').innerText = formatter.format(totalCashInvested);
document.getElementById('resTotalExp').innerText = formatter.format(totalMonthlyExpenses);
// Styling adjustments for negative flow
if (monthlyCashFlow < 0) {
document.getElementById('resCashFlow').style.color = "#e74c3c";
} else {
document.getElementById('resCashFlow').style.color = "#27ae60";
}
document.getElementById('resultsArea').style.display = "block";
}
Rental Property Cash Flow Calculator
Purchase Information
Income & Expenses
Financial Analysis
Monthly Net Cash Flow:
$0.00
Monthly NOI (Net Operating Income):
$0.00
Cash-on-Cash Return:
0.00%
Cap Rate:
0.00%
Total Cash Needed to Buy:
$0.00
Monthly Expenses (inc. Mortgage):
$0.00
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but it relies heavily on the numbers working in your favor. This Rental Property Cash Flow Calculator helps investors determine if a specific property will generate a profit (positive cash flow) or a loss (negative cash flow) on a monthly basis.
Key Metrics Explained
- Net Operating Income (NOI): This is your total income minus operating expenses (taxes, insurance, maintenance, etc.) excluding mortgage payments. It measures the property's potential profitability regardless of financing.
- Cash Flow: This is the money left in your pocket after paying ALL expenses, including the mortgage. Positive cash flow is the primary goal for buy-and-hold investors.
- Cash-on-Cash Return: This percentage tells you how hard your actual invested cash (down payment + closing costs) is working. A 10% CoC return means you earn $10 for every $100 invested annually.
- Cap Rate (Capitalization Rate): Calculated as NOI divided by the purchase price. It represents the natural rate of return of the property if you bought it in all cash.
How to Improve Cash Flow
If your calculation shows negative cash flow, you can try to improve the deal by negotiating a lower purchase price, increasing the down payment to lower the mortgage, or finding ways to increase rental income (e.g., adding amenities or reducing vacancy).
Estimating Expenses
When using the calculator, be realistic about expenses. Always budget for Vacancy (usually 5-8% depending on the market), Maintenance (5-10% of rent), and Capital Expenditures (big ticket items like roofs or HVAC). Underestimating these is the #1 reason new investors fail.