.calculator-wrapper {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
border: 1px solid #e0e0e0;
border-radius: 8px;
background: #fff;
padding: 20px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.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: 14px;
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus {
border-color: #0073aa;
outline: none;
}
.calc-btn {
grid-column: 1 / -1;
background-color: #0073aa;
color: white;
padding: 15px;
border: none;
border-radius: 4px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background 0.2s;
width: 100%;
margin-top: 10px;
}
.calc-btn:hover {
background-color: #005177;
}
.results-section {
margin-top: 30px;
background-color: #f9f9f9;
padding: 20px;
border-radius: 6px;
border-left: 5px solid #0073aa;
}
.result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #e0e0e0;
}
.result-row:last-child {
border-bottom: none;
}
.result-label {
font-weight: 500;
color: #555;
}
.result-value {
font-weight: 700;
color: #333;
font-size: 18px;
}
.cash-flow-positive {
color: #27ae60;
}
.cash-flow-negative {
color: #c0392b;
}
.content-section {
margin-top: 40px;
line-height: 1.6;
color: #444;
}
.content-section h2 {
color: #2c3e50;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
margin-top: 30px;
}
.content-section h3 {
color: #2c3e50;
margin-top: 25px;
}
.content-section p {
margin-bottom: 15px;
}
.content-section ul {
margin-bottom: 20px;
padding-left: 20px;
}
.tooltip {
font-size: 12px;
color: #777;
margin-top: 2px;
}
function calculateRentalCashFlow() {
// Get inputs
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value) || 0;
var interest = parseFloat(document.getElementById('interestRate').value) || 0;
var termYears = parseFloat(document.getElementById('loanTerm').value) || 30;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var annualTax = parseFloat(document.getElementById('annualTax').value) || 0;
var annualIns = parseFloat(document.getElementById('annualInsurance').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('monthlyHOA').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var closingCosts = parseFloat(document.getElementById('closingCosts').value) || 0;
// Calculations
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
// Mortgage Calculation (P&I)
var monthlyRate = (interest / 100) / 12;
var numberOfPayments = termYears * 12;
var monthlyMortgage = 0;
if (monthlyRate > 0 && loanAmount > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else if (loanAmount > 0) {
monthlyMortgage = loanAmount / numberOfPayments;
}
// Operating Expenses
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var monthlyVacancyAndMaint = rent * (vacancyRate / 100);
var totalOperatingExpenses = monthlyTax + monthlyIns + monthlyHOA + monthlyVacancyAndMaint;
var totalMonthlyExpenses = totalOperatingExpenses + monthlyMortgage;
// Cash Flow
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// Investment Returns
var totalCashInvested = downPaymentAmount + closingCosts;
var cashOnCash = 0;
if (totalCashInvested > 0) {
cashOnCash = (annualCashFlow / totalCashInvested) * 100;
}
// Cap Rate = (Net Operating Income / Current Market Value) * 100
// NOI = Annual Income – Annual Operating Expenses (Excluding Mortgage)
var annualNOI = (rent * 12) – (totalOperatingExpenses * 12);
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// Display Results
document.getElementById('resIncome').innerText = '$' + rent.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resExpenses').innerText = '$' + totalMonthlyExpenses.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resMortgage').innerText = '$' + monthlyMortgage.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
var cfElement = document.getElementById('resCashFlow');
cfElement.innerText = (monthlyCashFlow >= 0 ? '$' : '-$') + Math.abs(monthlyCashFlow).toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
if (monthlyCashFlow >= 0) {
cfElement.className = "result-value cash-flow-positive";
} else {
cfElement.className = "result-value cash-flow-negative";
}
document.getElementById('resCoC').innerText = cashOnCash.toFixed(2) + '%';
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + '%';
// Show results div
document.getElementById('results').style.display = 'block';
}
Rental Property Cash Flow Calculator
Estimated % of rent set aside for repairs/vacancy
Monthly Financial Summary
Monthly Rental Income:
$0.00
Total Monthly Expenses:
$0.00
Monthly Mortgage Payment (P&I):
$0.00
Net Monthly Cash Flow:
$0.00
Cash on Cash Return
0.00%
Cap Rate
0.00%
Understanding Rental Property Cash Flow
Analyzing a rental property before purchasing is crucial for any real estate investor. Cash flow is the net amount of money left over each month after all operating expenses and mortgage payments have been made. A positive cash flow indicates a profitable investment, while a negative cash flow means the property costs you money to hold.
Key Metrics Explained
- Cash Flow: The difference between your rental income and total expenses (Mortgage + Taxes + Insurance + HOA + Maintenance).
- Cash on Cash Return (CoC): A percentage that measures the annual return on the actual cash invested (Down payment + Closing costs). This is often considered the most important metric for investors using leverage.
- Cap Rate (Capitalization Rate): Calculated by dividing Net Operating Income (NOI) by the property value. It represents the potential return on investment if you paid all cash, helping to compare properties regardless of financing.
- Net Operating Income (NOI): Total revenue minus necessary operating expenses (excluding mortgage payments).
How to Calculate Rental Cash Flow
To manually calculate your monthly cash flow, follow this formula:
Cash Flow = Gross Rent – (Mortgage + Taxes + Insurance + HOA + Repairs/Vacancy Reserves)
Example Calculation
Imagine you buy a property for $250,000 with 20% down ($50,000). Your mortgage is approximately $1,264 (at 6.5% for 30 years).
If you rent it for $2,200 per month and your taxes, insurance, and maintenance reserves total $600, your calculation looks like this:
- Income: $2,200
- Total Expenses: $1,264 (Mortgage) + $600 (Ops) = $1,864
- Monthly Cash Flow: $336
This calculator helps you perform these calculations instantly to determine if a property meets your investment goals.