Rental Property Cash Flow Calculator
.rp-calculator-wrapper {
max-width: 800px;
margin: 0 auto;
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
color: #333;
background: #fff;
border: 1px solid #e0e0e0;
border-radius: 8px;
box-shadow: 0 4px 12px rgba(0,0,0,0.05);
overflow: hidden;
}
.rp-calc-header {
background: #2c3e50;
color: #fff;
padding: 20px;
text-align: center;
}
.rp-calc-header h2 {
margin: 0;
font-size: 24px;
}
.rp-calc-body {
padding: 25px;
display: flex;
flex-wrap: wrap;
gap: 30px;
}
.rp-input-section, .rp-results-section {
flex: 1;
min-width: 300px;
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.rp-input-group {
margin-bottom: 15px;
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font-weight: 600;
margin-bottom: 5px;
font-size: 14px;
color: #555;
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.rp-input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 15px;
box-sizing: border-box;
}
.rp-input-group input:focus {
border-color: #3498db;
outline: none;
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.rp-row {
display: flex;
gap: 15px;
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flex: 1;
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.rp-btn {
width: 100%;
padding: 12px;
background-color: #27ae60;
color: white;
border: none;
border-radius: 5px;
font-size: 16px;
font-weight: bold;
cursor: pointer;
transition: background 0.2s;
margin-top: 10px;
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.rp-btn:hover {
background-color: #219150;
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background: #f8f9fa;
border-left: 5px solid #3498db;
padding: 15px;
margin-bottom: 15px;
border-radius: 4px;
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background: #e8f8f5;
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.rp-result-label {
font-size: 13px;
color: #777;
text-transform: uppercase;
letter-spacing: 0.5px;
margin-bottom: 5px;
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.rp-result-value {
font-size: 22px;
font-weight: 700;
color: #2c3e50;
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.rp-result-value.positive { color: #27ae60; }
.rp-result-value.negative { color: #c0392b; }
.rp-article-content {
max-width: 800px;
margin: 40px auto;
padding: 0 20px;
line-height: 1.6;
color: #444;
}
.rp-article-content h2 { color: #2c3e50; margin-top: 30px; }
.rp-article-content h3 { color: #34495e; margin-top: 25px; }
.rp-article-content ul { padding-left: 20px; }
.rp-article-content li { margin-bottom: 10px; }
@media (max-width: 600px) {
.rp-row { flex-direction: column; gap: 0; }
}
Financial Metrics
Est. Monthly Cash Flow
$0.00
Cash on Cash Return (CoC)
0.00%
Net Operating Income (NOI) / Mo
$0.00
Total Cash Needed to Close
$0.00
Total Monthly Expenses
$0.00
function calculateRentalReturns() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('rpPrice').value) || 0;
var downPercent = parseFloat(document.getElementById('rpDown').value) || 0;
var interestRate = parseFloat(document.getElementById('rpRate').value) || 0;
var termYears = parseFloat(document.getElementById('rpTerm').value) || 0;
var rent = parseFloat(document.getElementById('rpRent').value) || 0;
var annualTax = parseFloat(document.getElementById('rpTax').value) || 0;
var annualIns = parseFloat(document.getElementById('rpIns').value) || 0;
var maintPercent = parseFloat(document.getElementById('rpMaint').value) || 0;
var vacancyPercent = parseFloat(document.getElementById('rpVacancy').value) || 0;
var mgmtPercent = parseFloat(document.getElementById('rpMgmt').value) || 0;
// 2. Calculate Mortgage Payment
var downPayment = price * (downPercent / 100);
var loanAmount = price – downPayment;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = termYears * 12;
var mortgagePayment = 0;
if (interestRate > 0 && loanAmount > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else if (loanAmount > 0 && interestRate === 0) {
mortgagePayment = loanAmount / numberOfPayments;
}
// 3. Calculate Monthly Expenses
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var monthlyMaint = rent * (maintPercent / 100);
var monthlyVacancy = rent * (vacancyPercent / 100);
var monthlyMgmt = rent * (mgmtPercent / 100);
// Operating Expenses (excluding mortgage)
var monthlyOperatingExpenses = monthlyTax + monthlyIns + monthlyMaint + monthlyVacancy + monthlyMgmt;
// Total Expenses (including mortgage)
var totalMonthlyExpenses = monthlyOperatingExpenses + mortgagePayment;
// 4. Calculate NOI and Cash Flow
var monthlyNOI = rent – monthlyOperatingExpenses;
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
var annualNOI = monthlyNOI * 12;
// 5. Calculate Returns
// Assume closing costs are roughly 2% of price for estimation of "Cash Needed"
var closingCosts = price * 0.02;
var totalCashInvested = downPayment + closingCosts;
var cocReturn = 0;
if (totalCashInvested > 0) {
cocReturn = (annualCashFlow / totalCashInvested) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// 6. Display Results
var cfElement = document.getElementById('rpResultCashFlow');
cfElement.innerText = formatCurrency(monthlyCashFlow);
cfElement.className = 'rp-result-value ' + (monthlyCashFlow >= 0 ? 'positive' : 'negative');
document.getElementById('rpResultCoC').innerText = cocReturn.toFixed(2) + '%';
document.getElementById('rpResultNOI').innerText = formatCurrency(monthlyNOI);
document.getElementById('rpResultCap').innerText = capRate.toFixed(2) + '%';
document.getElementById('rpResultCashNeeded').innerText = formatCurrency(totalCashInvested);
document.getElementById('rpResultExpenses').innerText = formatCurrency(totalMonthlyExpenses);
}
function formatCurrency(num) {
return '$' + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
// Initial calculation on load
calculateRentalReturns();
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. This Rental Property Calculator is designed to help investors accurately analyze the profitability of a potential purchase by accounting for all income and expense variables.
Why Cash Flow is King
Positive cash flow ensures that the property pays for itself while generating a surplus income for you. Negative cash flow means you are feeding the property monthly from your own pocket, which increases risk. Using a detailed calculator helps you avoid "alligator properties" that eat up your capital.
Key Metrics Explained
- Net Operating Income (NOI): This is your total income minus operating expenses (taxes, insurance, maintenance, vacancy) before paying the mortgage. It measures the raw profitability of the asset itself.
- Cash on Cash Return (CoC): This is perhaps the most important metric for ROI. It measures the annual cash income you receive relative to the actual cash you invested (down payment + closing costs). A CoC of 8-12% is often considered a solid target for rentals.
- Cap Rate (Capitalization Rate): Calculated as Annual NOI divided by the Purchase Price. This allows you to compare the profitability of different properties regardless of how they are financed.
Estimating Expenses Correctly
Novice investors often underestimate expenses. When using this calculator, ensure you factor in:
- Vacancy Rate: No property is occupied 100% of the time. A standard 5-8% deduction is prudent.
- Maintenance: Even if the house is new, things break. Budgeting 5-10% of the rent for repairs builds a safety net (CapEx).
- Management Fees: Even if you self-manage now, calculating a 10% fee ensures the deal still works if you hire a manager later.
How to Use This Tool
Start by entering the purchase price and your loan details. Be sure to input accurate tax and insurance figures, which can usually be found on local property listing sites (like Zillow or Redfin) or county assessor websites. Adjust the "Rental Income" to see how slight changes in rent affect your Cash on Cash return. Use the results to determine your maximum offer price.