#rental-calculator-widget .form-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
#rental-calculator-widget .form-grid {
grid-template-columns: 1fr;
}
}
#rental-calculator-widget label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #333;
font-size: 14px;
}
#rental-calculator-widget input, #rental-calculator-widget select {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
#rental-calculator-widget .section-title {
grid-column: 1 / -1;
font-size: 18px;
color: #2c3e50;
border-bottom: 2px solid #3498db;
padding-bottom: 10px;
margin-top: 20px;
margin-bottom: 10px;
}
#rental-calculator-widget button {
grid-column: 1 / -1;
background-color: #27ae60;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.3s;
margin-top: 10px;
}
#rental-calculator-widget button:hover {
background-color: #219150;
}
#rental-calculator-widget .results-container {
margin-top: 30px;
background-color: #f8f9fa;
padding: 20px;
border-radius: 8px;
border: 1px solid #e9ecef;
display: none; /* Hidden by default */
}
#rental-calculator-widget .result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #dee2e6;
}
#rental-calculator-widget .result-row:last-child {
border-bottom: none;
}
#rental-calculator-widget .result-label {
color: #555;
font-weight: 500;
}
#rental-calculator-widget .result-value {
font-weight: 700;
color: #2c3e50;
}
#rental-calculator-widget .main-metric {
font-size: 24px;
color: #27ae60;
}
#rental-calculator-widget .negative {
color: #c0392b;
}
.calc-article {
margin-top: 40px;
line-height: 1.6;
color: #444;
}
.calc-article h2 {
color: #2c3e50;
margin-top: 30px;
}
.calc-article h3 {
color: #34495e;
margin-top: 20px;
}
.calc-article ul {
margin-bottom: 20px;
}
.calc-article li {
margin-bottom: 10px;
}
function calculateRental() {
// Get Input Values
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var termYears = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var annualTax = parseFloat(document.getElementById('annualPropertyTax').value);
var annualIns = parseFloat(document.getElementById('annualInsurance').value);
var monthlyHOA = parseFloat(document.getElementById('monthlyHOA').value);
var maintRate = parseFloat(document.getElementById('maintenanceRate').value);
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value);
var mgmtRate = parseFloat(document.getElementById('managementRate').value);
// Validation
if (isNaN(price) || isNaN(rent) || isNaN(interestRate)) {
alert("Please enter valid numbers for all fields.");
return;
}
// Loan Calculation
var downPaymentAmt = price * (downPercent / 100);
var loanAmount = price – downPaymentAmt;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = termYears * 12;
// Monthly Mortgage Payment (PI)
var monthlyPI = 0;
if (interestRate === 0) {
monthlyPI = loanAmount / numberOfPayments;
} else {
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// Monthly Expenses Breakdown
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var monthlyMaint = rent * (maintRate / 100);
var monthlyVacancy = rent * (vacancyRate / 100);
var monthlyMgmt = rent * (mgmtRate / 100);
// Total Expenses
var operatingExpenses = monthlyTax + monthlyIns + monthlyHOA + monthlyMaint + monthlyVacancy + monthlyMgmt;
var totalExpenses = operatingExpenses + monthlyPI;
// Cash Flow
var cashFlow = rent – totalExpenses;
var annualCashFlow = cashFlow * 12;
// NOI (Net Operating Income) – Excludes Debt Service
var annualOperatingExpenses = operatingExpenses * 12;
var noi = (rent * 12) – annualOperatingExpenses;
// Returns
var capRate = (noi / price) * 100;
var cashOnCash = (annualCashFlow / downPaymentAmt) * 100;
if (downPaymentAmt === 0) cashOnCash = 0; // Avoid Infinity
// Display Results
var cashFlowEl = document.getElementById('monthlyCashFlow');
cashFlowEl.innerHTML = formatCurrency(cashFlow);
cashFlowEl.className = cashFlow >= 0 ? 'result-value main-metric' : 'result-value main-metric negative';
document.getElementById('annualNOI').innerHTML = formatCurrency(noi);
var cocEl = document.getElementById('cashOnCash');
cocEl.innerHTML = cashOnCash.toFixed(2) + "%";
cocEl.className = cashOnCash >= 0 ? 'result-value' : 'result-value negative';
document.getElementById('capRate').innerHTML = capRate.toFixed(2) + "%";
document.getElementById('monthlyPI').innerHTML = formatCurrency(monthlyPI);
document.getElementById('totalMonthlyExpenses').innerHTML = formatCurrency(totalExpenses);
// Show results section
document.getElementById('resultsArea').style.display = 'block';
}
function formatCurrency(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
About Rental Property Cash Flow
Analyzing a rental property before you buy is crucial for real estate investors. "Cash flow" represents the net amount of cash moving in or out of a business at a specific point in time. For rental properties, positive cash flow means the rental income exceeds all expenses, putting money in your pocket every month.
Understanding the Key Metrics
This calculator provides several critical metrics to help you evaluate the profitability of a potential investment property:
1. Monthly Cash Flow
This is your profit after paying all bills. It is calculated as Total Rent – (Mortgage + Taxes + Insurance + HOA + Reserves). A positive number indicates a profitable property, while a negative number means you will be paying out-of-pocket to hold the asset.
2. Net Operating Income (NOI)
NOI is a standard profitability metric used to analyze the value of real estate assets. It equals all revenue from the property minus all necessary operating expenses. Importantly, NOI does not include mortgage payments (debt service). It looks strictly at the property's ability to generate income regardless of financing structure.
3. Cap Rate (Capitalization Rate)
The Cap Rate is the ratio of Net Operating Income (NOI) to the property asset value (Current Market Value or Purchase Price). It helps compare the return of a property investment to other risk-free investments or other properties, ignoring financing.
Formula: Cap Rate = NOI / Purchase Price
4. Cash on Cash Return (CoC)
This metric measures the annual return the investor made on the property in relation to the amount of mortgage paid during the same year. It is considered one of the most important metrics because it calculates the return on the actual cash you invested (Down Payment).
Formula: CoC = Annual Pre-Tax Cash Flow / Total Cash Invested
Tips for Using This Calculator
- Vacancy Rate: Always budget for vacancy. 5-8% is a standard industry average (equivalent to about 3-4 weeks empty per year).
- Maintenance: Even new homes need repairs. Setting aside 5-10% of rent ensures you have funds for painting, plumbing, or appliance replacements.
- Management: If you plan to hire a property manager, expect to pay between 8-12% of the monthly rent.