.calculator-box {
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
padding: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
margin-bottom: 40px;
}
.calc-title {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 28px;
font-weight: 700;
}
.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: 8px;
font-weight: 600;
font-size: 14px;
color: #555;
}
.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: #3498db;
outline: none;
box-shadow: 0 0 5px rgba(52, 152, 219, 0.3);
}
.calc-btn {
width: 100%;
padding: 15px;
background-color: #27ae60;
color: white;
border: none;
border-radius: 4px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background 0.3s;
margin-top: 10px;
}
.calc-btn:hover {
background-color: #219150;
}
.results-section {
margin-top: 30px;
padding: 20px;
background: #fff;
border: 1px solid #ddd;
border-radius: 4px;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.result-row:last-child {
border-bottom: none;
}
.result-label {
font-weight: 600;
color: #555;
}
.result-value {
font-weight: 700;
color: #2c3e50;
}
.cash-flow-highlight {
color: #27ae60;
font-size: 20px;
}
.negative-flow {
color: #e74c3c;
}
.article-content {
line-height: 1.6;
color: #444;
}
.article-content h2 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
}
.article-content p {
margin-bottom: 15px;
}
.article-content ul {
margin-bottom: 20px;
padding-left: 20px;
}
.article-content li {
margin-bottom: 8px;
}
.tooltip {
font-size: 12px;
color: #777;
margin-top: 4px;
}
function calculateRental() {
// Get Inputs
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var downPayment = parseFloat(document.getElementById('downPayment').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var loanTerm = parseFloat(document.getElementById('loanTerm').value) || 0;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var otherIncome = parseFloat(document.getElementById('otherIncome').value) || 0;
var propertyTax = parseFloat(document.getElementById('propertyTax').value) || 0;
var insurance = parseFloat(document.getElementById('insurance').value) || 0;
var repairPct = parseFloat(document.getElementById('repairCost').value) || 0;
var vacancyPct = parseFloat(document.getElementById('vacancyRate').value) || 0;
var capexPct = parseFloat(document.getElementById('capex').value) || 0;
var mgmtPct = parseFloat(document.getElementById('managementFee').value) || 0;
// Validate critical inputs
if (price <= 0 || loanTerm 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
} else {
monthlyMortgage = loanAmount / numPayments;
}
// Income Calculations
var totalMonthlyIncome = rent + otherIncome;
var annualIncome = totalMonthlyIncome * 12;
// Monthly Expense Calculations
var monthlyTax = propertyTax / 12;
var monthlyIns = insurance / 12;
var monthlyRepairs = totalMonthlyIncome * (repairPct / 100);
var monthlyVacancy = totalMonthlyIncome * (vacancyPct / 100);
var monthlyCapex = totalMonthlyIncome * (capexPct / 100);
var monthlyMgmt = totalMonthlyIncome * (mgmtPct / 100);
var operatingExpenses = monthlyTax + monthlyIns + monthlyRepairs + monthlyVacancy + monthlyCapex + monthlyMgmt;
var totalExpenses = operatingExpenses + monthlyMortgage;
// Key Metrics
var monthlyCashFlow = totalMonthlyIncome – totalExpenses;
var annualCashFlow = monthlyCashFlow * 12;
var monthlyNOI = totalMonthlyIncome – operatingExpenses;
var annualNOI = monthlyNOI * 12;
// ROI Calculations
var cashInvested = downPayment; // Keeping simple, could add closing costs input later
var cashOnCash = 0;
if (cashInvested > 0) {
cashOnCash = (annualCashFlow / cashInvested) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// Format formatting helper
var fmtMoney = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
// Display Results
document.getElementById('resGrossIncome').innerText = fmtMoney.format(totalMonthlyIncome);
document.getElementById('resMortgage').innerText = fmtMoney.format(monthlyMortgage);
document.getElementById('resOperatingExp').innerText = fmtMoney.format(operatingExpenses);
var cashFlowEl = document.getElementById('resCashFlow');
cashFlowEl.innerText = fmtMoney.format(monthlyCashFlow);
if(monthlyCashFlow >= 0) {
cashFlowEl.className = "result-value cash-flow-highlight";
} else {
cashFlowEl.className = "result-value negative-flow";
}
document.getElementById('resCoC').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resNOI').innerText = fmtMoney.format(annualNOI);
// Show results div
document.getElementById('results').style.display = 'block';
}
Rental Property Cash Flow Calculator
Laundry, parking, etc.
% of monthly rent
Avg 5-8% recommended
Roof, HVAC savings
Usually 8-10% if hired
Monthly Analysis
Gross Monthly Income:
$0.00
Principal & Interest (Mortgage):
$0.00
Total Operating Expenses:
$0.00
Net Monthly Cash Flow:
$0.00
Investment Returns
Cash on Cash Return (ROI):
0.00%
Cap Rate:
0.00%
Net Operating Income (NOI – Annual):
$0.00
How to Analyze a Rental Property Investment
Investing in real estate is a powerful way to build wealth, but it relies heavily on the numbers. Unlike purchasing a primary residence based on emotion, buying a rental property is strictly a business decision. This Rental Property Cash Flow Calculator helps you break down the income, expenses, and ultimate return on investment (ROI) of a potential deal.
Understanding Key Real Estate Metrics
When evaluating a property, successful investors look beyond just the monthly rent. Here are the critical metrics calculated above:
- Cash Flow: This is the net profit you pocket every month after all bills are paid. It is calculated as Total Income – Total Expenses (Mortgage + Operating Costs). Positive cash flow ensures the property pays for itself and provides passive income.
- Cash on Cash Return (CoC): This measures the efficiency of the cash you actually invested. It is calculated as Annual Pre-Tax Cash Flow / Total Cash Invested. This allows you to compare real estate returns against stocks or bonds.
- Cap Rate (Capitalization Rate): This metric evaluates the profitability of the property itself, independent of financing. It is calculated as Net Operating Income (NOI) / Property Purchase Price. A higher Cap Rate generally indicates a better return, though it may come with higher risk.
- Net Operating Income (NOI): This is the total income minus all operating expenses (taxes, insurance, repairs, vacancy), but excluding mortgage payments. Lenders use this to determine if the property generates enough income to cover the debt.
Estimating "Hidden" Expenses
Many new investors make the mistake of only subtracting the mortgage payment from the rent. To get an accurate picture, you must account for variable expenses:
- Vacancy Rate: Properties won't be rented 365 days a year. A standard conservative estimate is 5-8% (about 2-3 weeks of vacancy per year).
- Maintenance & CapEx: Toilets break and roofs leak. Setting aside 5-10% of the rent for repairs (Maintenance) and major replacements (Capital Expenditures or CapEx) ensures you aren't caught off guard by a big bill.
- Property Management: Even if you plan to self-manage, it is wise to factor in a 8-10% management fee. This ensures the deal still works if you later decide to hire a professional manager.
The 1% Rule and 50% Rule
For quick screening before using a detailed calculator, investors often use "rules of thumb":
The 1% Rule suggests that the monthly rent should be at least 1% of the purchase price. For example, a $200,000 house should rent for at least $2,000/month.
The 50% Rule estimates that 50% of your gross rent will go toward operating expenses (excluding the mortgage). If a property rents for $2,000, expect $1,000 to leave as expenses, leaving $1,000 to cover the mortgage and profit.
Use the calculator above to move beyond these estimates and get precise numbers for your specific investment scenario.