.calculator-container {
font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
padding: 20px;
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
}
.calc-grid {
display: flex;
flex-wrap: wrap;
gap: 20px;
}
.calc-col {
flex: 1;
min-width: 300px;
}
.calc-input-group {
margin-bottom: 15px;
}
.calc-input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #333;
}
.calc-input-group input, .calc-input-group select {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
}
.calc-btn {
background-color: #2c3e50;
color: white;
padding: 12px 20px;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 16px;
width: 100%;
margin-top: 10px;
transition: background 0.3s;
}
.calc-btn:hover {
background-color: #34495e;
}
.calc-results {
background: #fff;
padding: 20px;
border-radius: 8px;
border: 1px solid #ddd;
margin-top: 20px;
}
.result-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
padding-bottom: 10px;
border-bottom: 1px solid #eee;
}
.result-row:last-child {
border-bottom: none;
}
.result-label {
color: #666;
}
.result-value {
font-weight: bold;
color: #2c3e50;
}
.final-result {
font-size: 1.2em;
color: #27ae60;
margin-top: 10px;
padding-top: 10px;
border-top: 2px solid #eee;
}
.negative-flow {
color: #c0392b;
}
.calc-article {
margin-top: 40px;
line-height: 1.6;
color: #444;
}
.calc-article h2 {
color: #2c3e50;
margin-top: 30px;
}
.calc-article ul {
margin-bottom: 20px;
}
function calculateRental() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var down = parseFloat(document.getElementById('downPayment').value) || 0;
var closing = parseFloat(document.getElementById('closingCosts').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var termYears = parseInt(document.getElementById('loanTerm').value) || 30;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var taxYear = parseFloat(document.getElementById('propTax').value) || 0;
var insYear = parseFloat(document.getElementById('insurance').value) || 0;
var hoa = parseFloat(document.getElementById('hoa').value) || 0;
var maint = parseFloat(document.getElementById('maintenance').value) || 0;
var vacancyPct = parseFloat(document.getElementById('vacancy').value) || 0;
// 2. Perform Calculations
// Loan Amount
var loanAmount = price – down;
// Monthly Mortgage Calculation (M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ])
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = termYears * 12;
var mortgagePayment = 0;
if (monthlyRate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
mortgagePayment = loanAmount / numberOfPayments;
}
// Other Monthly Expenses
var monthlyTax = taxYear / 12;
var monthlyIns = insYear / 12;
var vacancyCost = rent * (vacancyPct / 100);
var totalMonthlyExpenses = mortgagePayment + monthlyTax + monthlyIns + hoa + maint + vacancyCost;
// Operating Expenses (Expenses excluding mortgage – for NOI)
var operatingExpenses = monthlyTax + monthlyIns + hoa + maint + vacancyCost;
// Cash Flow
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// Net Operating Income (Monthly)
var monthlyNOI = rent – operatingExpenses;
// Total Cash Invested
var totalInvested = down + closing;
// Cash on Cash ROI
var roi = 0;
if (totalInvested > 0) {
roi = (annualCashFlow / totalInvested) * 100;
}
// 3. Update UI
document.getElementById('resultsArea').style.display = 'block';
// Helper for formatting currency
var fmt = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
document.getElementById('displayMortgage').innerHTML = fmt.format(mortgagePayment);
document.getElementById('displayExpenses').innerHTML = fmt.format(totalMonthlyExpenses);
document.getElementById('displayNOI').innerHTML = fmt.format(monthlyNOI);
var cashFlowElem = document.getElementById('displayCashFlow');
cashFlowElem.innerHTML = fmt.format(monthlyCashFlow);
if (monthlyCashFlow >= 0) {
cashFlowElem.className = 'result-value';
cashFlowElem.style.color = '#27ae60';
} else {
cashFlowElem.className = 'result-value negative-flow';
cashFlowElem.style.color = '#c0392b';
}
var roiElem = document.getElementById('displayROI');
roiElem.innerHTML = roi.toFixed(2) + '%';
if (roi >= 0) {
roiElem.style.color = '#27ae60';
} else {
roiElem.style.color = '#c0392b';
}
}
Rental Property Cash Flow Calculator
Purchase Details
30 Years
15 Years
Income & Expenses
Monthly Mortgage P&I:
$0.00
Total Monthly Expenses:
$0.00
Monthly Net Operating Income (NOI):
$0.00
Monthly Cash Flow:
$0.00
Cash on Cash ROI:
0.00%
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but the difference between a successful investment and a financial burden often comes down to one metric: Cash Flow. Our Rental Property Cash Flow Calculator helps you evaluate the potential profitability of an investment property before you sign on the dotted line.
What is Cash Flow?
Cash flow is the net amount of cash moving in and out of a business or investment. In real estate, positive cash flow means your property's income (primarily rent) exceeds all expenses, including the mortgage, taxes, insurance, and maintenance. Negative cash flow means you are losing money every month to hold the property.
Key Metrics Explained
- NOI (Net Operating Income): This is your total income minus operating expenses, excluding mortgage payments. It measures the profitability of the property itself.
- Cash on Cash ROI: This is arguably the most important metric for investors. It calculates the annual return you are making on the actual cash you invested (Down Payment + Closing Costs), rather than the total price of the property.
- Vacancy Rate: No property is occupied 100% of the time. A safe estimate is usually 5-8%, which accounts for turnover periods between tenants.
Real-World Example
Let's look at a realistic scenario using the calculator above:
Imagine you find a property for $250,000. You put $50,000 down (20%) and pay $5,000 in closing costs. You secure a loan at 6.5% interest for 30 years.
If you can rent the property for $2,200/month, and your total monthly expenses (mortgage, taxes, insurance, maintenance, vacancy buffer) come out to roughly $2,000, your positive cash flow is $200/month.
While $200 might seem small, your Cash on Cash ROI would be calculated based on the annual return ($2,400) divided by your total cash invested ($55,000), resulting in a 4.36% return—and this doesn't even account for property appreciation or loan principal paydown!
How to Improve Your Cash Flow
If the calculator shows a negative or low cash flow, consider these strategies:
- Increase Rent: Can minor cosmetic upgrades justify a higher monthly rent?
- Lower Expenses: Shop around for cheaper insurance or challenge your property tax assessment.
- Larger Down Payment: Putting more money down reduces your monthly mortgage payment, instantly boosting cash flow.