:root {
–primary-color: #2c3e50;
–accent-color: #27ae60;
–bg-color: #f8f9fa;
–text-color: #333;
–border-radius: 8px;
}
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: var(–text-color);
margin: 0;
padding: 0;
}
.calculator-container {
max-width: 800px;
margin: 20px auto;
background: #fff;
padding: 30px;
border-radius: var(–border-radius);
box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
.calc-header {
text-align: center;
margin-bottom: 30px;
}
.calc-header h2 {
color: var(–primary-color);
margin: 0;
}
.input-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.input-grid {
grid-template-columns: 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 0.9em;
color: var(–primary-color);
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus {
border-color: var(–accent-color);
outline: none;
}
.calc-btn-container {
text-align: center;
margin: 25px 0;
}
.calc-btn {
background-color: var(–accent-color);
color: white;
border: none;
padding: 12px 30px;
font-size: 18px;
font-weight: bold;
border-radius: var(–border-radius);
cursor: pointer;
transition: background-color 0.3s;
}
.calc-btn:hover {
background-color: #219150;
}
.results-section {
background-color: var(–bg-color);
padding: 20px;
border-radius: var(–border-radius);
margin-top: 20px;
border-left: 5px solid var(–accent-color);
display: none;
}
.results-grid {
display: grid;
grid-template-columns: repeat(3, 1fr);
gap: 15px;
margin-bottom: 20px;
}
@media (max-width: 600px) {
.results-grid {
grid-template-columns: 1fr;
}
}
.result-card {
background: white;
padding: 15px;
border-radius: 6px;
text-align: center;
box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}
.result-card h4 {
margin: 0 0 10px 0;
font-size: 0.85em;
color: #777;
text-transform: uppercase;
}
.result-value {
font-size: 1.4em;
font-weight: 800;
color: var(–primary-color);
}
.positive { color: var(–accent-color); }
.negative { color: #c0392b; }
.breakdown-table {
width: 100%;
border-collapse: collapse;
margin-top: 15px;
font-size: 0.9em;
}
.breakdown-table th, .breakdown-table td {
padding: 10px;
border-bottom: 1px solid #eee;
text-align: left;
}
.breakdown-table th {
color: var(–primary-color);
}
.breakdown-table td:last-child {
text-align: right;
font-weight: 600;
}
/* SEO Content Styling */
.content-container {
max-width: 800px;
margin: 40px auto;
padding: 0 20px;
}
.content-container h2 {
color: var(–primary-color);
border-bottom: 2px solid var(–accent-color);
padding-bottom: 10px;
margin-top: 30px;
}
.content-container h3 {
color: #34495e;
margin-top: 25px;
}
.content-container p, .content-container ul {
color: #555;
font-size: 1.05em;
}
.content-container ul {
margin-left: 20px;
}
.example-box {
background-color: #e8f6f3;
padding: 20px;
border-radius: 8px;
margin: 20px 0;
}
function calculateROI() {
// 1. Get Inputs and Handle Edge Cases
var purchasePrice = parseFloat(document.getElementById('purchasePrice').value) || 0;
var closingCosts = parseFloat(document.getElementById('closingCosts').value) || 0;
var downPaymentPercent = parseFloat(document.getElementById('downPaymentPercent').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var loanTerm = parseFloat(document.getElementById('loanTerm').value) || 30;
var monthlyRent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var yearlyTax = parseFloat(document.getElementById('propertyTax').value) || 0;
var yearlyInsurance = parseFloat(document.getElementById('insurance').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('hoa').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var maintenanceRate = parseFloat(document.getElementById('maintenanceRate').value) || 0;
var managementRate = parseFloat(document.getElementById('managementRate').value) || 0;
// 2. Initial Calculations
var downPaymentAmount = purchasePrice * (downPaymentPercent / 100);
var loanAmount = purchasePrice – downPaymentAmount;
var totalCashInvested = downPaymentAmount + closingCosts;
// 3. Mortgage Calculation (P&I)
var monthlyInterest = interestRate / 100 / 12;
var totalPayments = loanTerm * 12;
var monthlyMortgage = 0;
if (interestRate === 0) {
monthlyMortgage = loanAmount / totalPayments;
} else {
monthlyMortgage = loanAmount * (monthlyInterest * Math.pow(1 + monthlyInterest, totalPayments)) / (Math.pow(1 + monthlyInterest, totalPayments) – 1);
}
// Handle case where loan amount is 0 (100% down)
if (loanAmount 0) {
cashOnCashReturn = (annualCashFlow / totalCashInvested) * 100;
}
var capRate = 0;
if (purchasePrice > 0) {
capRate = ((netOperatingIncome * 12) / purchasePrice) * 100;
}
// 7. Format Helper
function formatCurrency(num) {
return '$' + num.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
}
function formatPercent(num) {
return num.toFixed(2) + '%';
}
// 8. Update DOM
var resultSection = document.getElementById('resultsSection');
resultSection.style.display = 'block';
// Summary Cards
var cfElement = document.getElementById('monthlyCashFlow');
cfElement.innerText = formatCurrency(monthlyCashFlow);
cfElement.className = monthlyCashFlow >= 0 ? 'result-value positive' : 'result-value negative';
var cocElement = document.getElementById('cashOnCash');
cocElement.innerText = formatPercent(cashOnCashReturn);
cocElement.className = cashOnCashReturn >= 0 ? 'result-value positive' : 'result-value negative';
document.getElementById('capRate').innerText = formatPercent(capRate);
// Breakdown Table
document.getElementById('displayRent').innerText = formatCurrency(monthlyRent);
document.getElementById('displayVacancy').innerText = '-' + formatCurrency(monthlyVacancy);
document.getElementById('displayOpIncome').innerText = formatCurrency(effectiveGrossIncome);
document.getElementById('displayTaxes').innerText = '-' + formatCurrency(monthlyTax);
document.getElementById('displayInsurance').innerText = '-' + formatCurrency(monthlyInsurance);
document.getElementById('displayMaint').innerText = '-' + formatCurrency(monthlyMaintenance);
document.getElementById('displayMgmt').innerText = '-' + formatCurrency(monthlyManagement);
document.getElementById('displayHOA').innerText = '-' + formatCurrency(monthlyHOA);
document.getElementById('displayNOI').innerText = formatCurrency(netOperatingIncome);
document.getElementById('displayMortgage').innerText = '-' + formatCurrency(monthlyMortgage);
document.getElementById('displayFinalCashFlow').innerText = formatCurrency(monthlyCashFlow);
}
How to Calculate Rental Property Cash Flow
Successful real estate investing relies on accurate math, not gut feelings. This Rental Property Cash Flow Calculator helps you evaluate whether a potential investment will generate income or drain your bank account. By inputting specific property data, you can derive three critical metrics used by professional investors:
1. Net Operating Income (NOI)
NOI is the total income the property generates after paying all operating expenses, but before paying the mortgage. It is calculated as:
- Formula: (Rental Income – Vacancy) – (Taxes + Insurance + Maintenance + Management + HOA)
- Why it matters: NOI tells you the raw profitability of the asset itself, regardless of how you financed it.
2. Cash Flow
Cash flow is the "take-home pay" from your investment. It is the money left over after every single expense, including the mortgage payment, has been paid.
- Formula: NOI – Mortgage Payment (Principal & Interest)
- Target: Most investors aim for at least $100-$200 per door in positive monthly cash flow to ensure a safety margin.
3. Cash on Cash Return (CoC)
This metric measures the return on the actual cash you invested (down payment + closing costs), rather than the total loan amount. It allows you to compare real estate returns against other investments like stocks or bonds.
- Formula: (Annual Cash Flow / Total Cash Invested) × 100
- Example: If you invest $50,000 cash to buy a house and it earns you $5,000 a year in profit, your CoC return is 10%.
Real World Example
Imagine you are purchasing a rental property for $200,000. You put 20% down ($40,000) and pay $5,000 in closing costs. Your total cash invested is $45,000.
The property rents for $2,000/month. After accounting for a mortgage payment of roughly $1,000 and operating expenses (taxes, insurance, repairs) of $600, your monthly cash flow is $400.
Annual Cash Flow: $400 × 12 = $4,800.
Cash on Cash Return: $4,800 / $45,000 = 10.66%.
Use the calculator above to run these numbers on your own potential deals.
Frequently Asked Questions
What is a good Cap Rate?
Capitalization Rate (Cap Rate) measures the rate of return on a real estate investment property based on the income that the property is expected to generate. A "good" cap rate varies by market, but generally, 4% to 5% is common in high-demand areas, while 8% to 10% is targeted in riskier or lower-cost areas.
Why include vacancy and maintenance?
Beginners often forget these costs. Properties will not be occupied 100% of the time, and things will break. Allocating 5% to 10% of rent for each of these categories creates a realistic budget so you aren't surprised by future costs.