.rp-calculator-wrapper {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 800px;
margin: 0 auto;
color: #333;
line-height: 1.6;
}
.rp-calc-container {
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
padding: 25px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
margin-bottom: 30px;
}
.rp-calc-title {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 24px;
font-weight: 700;
}
.rp-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.rp-grid {
grid-template-columns: 1fr;
}
}
.rp-input-group {
margin-bottom: 15px;
}
.rp-input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 14px;
color: #555;
}
.rp-input-group input, .rp-input-group select {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box; /* Critical for padding */
}
.rp-input-group input:focus {
border-color: #3498db;
outline: none;
}
.rp-section-header {
grid-column: 1 / -1;
font-size: 18px;
color: #3498db;
border-bottom: 2px solid #3498db;
padding-bottom: 5px;
margin-top: 10px;
margin-bottom: 15px;
}
.rp-btn {
grid-column: 1 / -1;
background-color: #27ae60;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 5px;
cursor: pointer;
transition: background 0.3s;
margin-top: 10px;
width: 100%;
}
.rp-btn:hover {
background-color: #219150;
}
.rp-results {
margin-top: 30px;
padding: 20px;
background: #fff;
border: 1px solid #ddd;
border-radius: 5px;
display: none; /* Hidden by default */
}
.rp-result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.rp-result-row:last-child {
border-bottom: none;
}
.rp-result-label {
font-weight: 600;
color: #555;
}
.rp-result-value {
font-weight: bold;
color: #2c3e50;
}
.rp-highlight {
color: #27ae60;
font-size: 1.2em;
}
.rp-highlight-neg {
color: #c0392b;
font-size: 1.2em;
}
.rp-article {
background: #fff;
padding: 20px;
}
.rp-article h2 {
color: #2c3e50;
margin-top: 0;
}
.rp-article h3 {
color: #34495e;
margin-top: 20px;
}
.rp-article ul {
padding-left: 20px;
}
.rp-article li {
margin-bottom: 10px;
}
function calculateRentalROI() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPercent = parseFloat(document.getElementById('downPayment').value);
var closingCosts = parseFloat(document.getElementById('closingCosts').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var years = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var taxYear = parseFloat(document.getElementById('propertyTax').value);
var insuranceYear = parseFloat(document.getElementById('insurance').value);
var hoaMonth = parseFloat(document.getElementById('hoa').value);
var vacancyPercent = parseFloat(document.getElementById('vacancyRate').value);
var maintPercent = parseFloat(document.getElementById('maintenanceRate').value);
// Validation
if (isNaN(price) || isNaN(downPercent) || isNaN(rent) || isNaN(rate)) {
alert("Please enter valid numbers for Price, Down Payment, Rent, and Interest Rate.");
return;
}
// 2. Calculate Initial Investment
var downAmount = price * (downPercent / 100);
var loanAmount = price – downAmount;
var totalInitialInvest = downAmount + closingCosts;
// 3. Calculate Mortgage Payment (P&I)
// M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
var monthlyRate = rate / 100 / 12;
var numberOfPayments = years * 12;
var monthlyMortgage = 0;
if (rate === 0) {
monthlyMortgage = loanAmount / numberOfPayments;
} else {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// 4. Calculate Monthly Expenses
var monthlyTax = taxYear / 12;
var monthlyIns = insuranceYear / 12;
var vacancyCost = rent * (vacancyPercent / 100);
var maintCost = rent * (maintPercent / 100);
var totalOperatingExpenses = monthlyTax + monthlyIns + hoaMonth + vacancyCost + maintCost;
var totalMonthlyOutflow = monthlyMortgage + totalOperatingExpenses;
// 5. Calculate Cash Flow
var monthlyCashFlow = rent – totalMonthlyOutflow;
var annualCashFlow = monthlyCashFlow * 12;
// 6. Calculate ROI & Cap Rate
// ROI = Annual CF / Total Initial Investment
var roi = (annualCashFlow / totalInitialInvest) * 100;
// NOI for Cap Rate = (Rent * 12) – (Annual Operating Expenses NOT including mortgage)
var annualOperatingExpenses = totalOperatingExpenses * 12;
var noi = (rent * 12) – annualOperatingExpenses;
var capRate = (noi / price) * 100;
// 7. Display Results
document.getElementById('rpResults').style.display = 'block';
// Formatting helper
var formatCurrency = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
document.getElementById('resInitialInvest').innerHTML = formatCurrency.format(totalInitialInvest);
document.getElementById('resMortgage').innerHTML = formatCurrency.format(monthlyMortgage);
document.getElementById('resTotalExp').innerHTML = formatCurrency.format(totalMonthlyOutflow);
var cfElement = document.getElementById('resMonthlyCF');
cfElement.innerHTML = formatCurrency.format(monthlyCashFlow);
cfElement.className = monthlyCashFlow >= 0 ? 'rp-result-value rp-highlight' : 'rp-result-value rp-highlight-neg';
var annCfElement = document.getElementById('resAnnualCF');
annCfElement.innerHTML = formatCurrency.format(annualCashFlow);
annCfElement.className = annualCashFlow >= 0 ? 'rp-result-value' : 'rp-result-value rp-highlight-neg';
var roiElement = document.getElementById('resROI');
roiElement.innerHTML = roi.toFixed(2) + '%';
roiElement.className = roi >= 0 ? 'rp-result-value rp-highlight' : 'rp-result-value rp-highlight-neg';
document.getElementById('resCapRate').innerHTML = capRate.toFixed(2) + '%';
}
Rental Property Cash Flow Calculator
Purchase Information
30 Years
15 Years
Income & Expenses
Analysis Results
Total Initial Investment (Cash to Close):
$0.00
Monthly Mortgage (P&I):
$0.00
Total Monthly Expenses (incl. Mortgage):
$0.00
Net Monthly Cash Flow:
$0.00
Annual Cash Flow:
$0.00
Cash on Cash ROI:
0.00%
Cap Rate:
0.00%
Understanding Rental Property Cash Flow Analysis
Investing in real estate is a numbers game. Unlike buying a personal home where emotion plays a large role, an investment property must make financial sense. This Rental Property Cash Flow Calculator helps investors determine if a potential deal will generate positive income or become a financial burden.
Key Metrics Explained
- Cash Flow: This is your profit after all expenses are paid. It is calculated as Gross Income – (Mortgage + Operating Expenses). Positive cash flow ensures the property pays for itself and provides you with income.
- Cash on Cash ROI (Return on Investment): This is arguably the most important metric for rental investors. It measures the return on the actual cash you invested (Down Payment + Closing Costs), rather than the total price of the property. A generic rule of thumb for a "good" ROI is 8-12%, though this varies by market.
- Cap Rate (Capitalization Rate): This measures the property's natural rate of return assuming you bought it with all cash. It helps compare properties irrespective of financing terms.
Hidden Expenses to Watch For
Many new investors fail because they underestimate expenses. This calculator includes inputs for:
- Vacancy Rate: You won't have a tenant 100% of the time. Setting aside 5-8% of rent ensures you are covered during turnover periods.
- Maintenance & CapEx: Roofs leak and toilets break. Allocating 5-10% of monthly rent to a maintenance fund prevents large repair bills from destroying your annual profit.
How to Interpret Your Results
If your Cash on Cash ROI is negative, the property will cost you money to hold every month. While some investors accept this banking on future appreciation, it is generally considered a high-risk strategy. Aim for positive monthly cash flow to ensure the asset is self-sustaining.