#rental-calculator-wrapper h2 { text-align: center; color: #2c3e50; margin-bottom: 25px; }
.calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
@media (max-width: 768px) { .calc-grid { grid-template-columns: 1fr; } }
.calc-input-group { margin-bottom: 15px; }
.calc-input-group label { display: block; margin-bottom: 5px; font-weight: 600; color: #555; font-size: 14px; }
.calc-input-group input { width: 100%; padding: 10px; border: 1px solid #ddd; border-radius: 4px; font-size: 16px; box-sizing: border-box; }
.calc-input-group input:focus { border-color: #3498db; outline: none; box-shadow: 0 0 5px rgba(52,152,219,0.3); }
.calc-section-title { grid-column: 1 / -1; font-size: 18px; color: #2980b9; border-bottom: 2px solid #eee; padding-bottom: 10px; margin-top: 20px; margin-bottom: 15px; font-weight: bold; }
.calc-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%; }
.calc-btn:hover { background-color: #219150; }
#calc-results { margin-top: 30px; background-color: #f8f9fa; padding: 20px; border-radius: 6px; border-left: 5px solid #27ae60; display: none; }
.result-row { display: flex; justify-content: space-between; margin-bottom: 12px; font-size: 15px; border-bottom: 1px dashed #e0e0e0; padding-bottom: 5px; }
.result-row.main-result { font-size: 20px; font-weight: bold; color: #2c3e50; border-bottom: none; margin-top: 15px; padding-top: 10px; border-top: 2px solid #ddd; }
.positive-cf { color: #27ae60; }
.negative-cf { color: #c0392b; }
.calc-article { margin-top: 40px; line-height: 1.6; color: #333; }
.calc-article h3 { color: #2c3e50; margin-top: 25px; }
.calc-article p { margin-bottom: 15px; }
.calc-article ul { margin-bottom: 15px; padding-left: 20px; }
.calc-article li { margin-bottom: 8px; }
function calculateRental() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('propPrice').value);
var downPercent = parseFloat(document.getElementById('downPayment').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var loanYears = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var taxYearly = parseFloat(document.getElementById('annualTax').value);
var insYearly = parseFloat(document.getElementById('annualIns').value);
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value);
var mgmtFee = parseFloat(document.getElementById('mgmtFee').value);
var repairRate = parseFloat(document.getElementById('repairCost').value);
// Validation
if (isNaN(price) || isNaN(downPercent) || isNaN(interestRate) || isNaN(loanYears) || isNaN(rent)) {
alert("Please enter valid numbers for all primary fields.");
return;
}
// 2. Calculate Mortgage (Principal & Interest)
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (interestRate / 100) / 12;
var totalMonths = loanYears * 12;
var monthlyMortgage = 0;
if (interestRate > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, totalMonths)) / (Math.pow(1 + monthlyRate, totalMonths) – 1);
} else {
monthlyMortgage = loanAmount / totalMonths;
}
// 3. Calculate Operating Expenses
var monthlyTax = taxYearly / 12;
var monthlyIns = insYearly / 12;
var vacancyCost = rent * (vacancyRate / 100);
var mgmtCost = rent * (mgmtFee / 100);
var repairCost = rent * (repairRate / 100);
var totalMonthlyExpenses = monthlyMortgage + monthlyTax + monthlyIns + vacancyCost + mgmtCost + repairCost;
// 4. Calculate NOI (Net Operating Income)
// NOI excludes Mortgage P&I
var operatingExpensesOnly = monthlyTax + monthlyIns + vacancyCost + mgmtCost + repairCost;
var monthlyNOI = rent – operatingExpensesOnly;
var annualNOI = monthlyNOI * 12;
// 5. Calculate Cash Flow
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// 6. Calculate Returns
var capRate = (annualNOI / price) * 100;
// Cash Invested = Down Payment (Simplifying closing costs to 0 for this tool, or we assume included)
var cashInvested = downPaymentAmount;
var cocReturn = 0;
if (cashInvested > 0) {
cocReturn = (annualCashFlow / cashInvested) * 100;
}
// 7. Update UI
document.getElementById('resMortgage').innerText = "$" + monthlyMortgage.toFixed(2);
document.getElementById('resExpenses').innerText = "$" + totalMonthlyExpenses.toFixed(2);
document.getElementById('resNOI').innerText = "$" + monthlyNOI.toFixed(2);
var cfElement = document.getElementById('resCashFlow');
cfElement.innerText = "$" + monthlyCashFlow.toFixed(2);
// Style result based on positive/negative
if (monthlyCashFlow >= 0) {
cfElement.className = "positive-cf";
} else {
cfElement.className = "negative-cf";
}
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resCOC').innerText = cocReturn.toFixed(2) + "%";
// Show Results
document.getElementById('calc-results').style.display = "block";
}
Rental Property Cash Flow Calculator
Purchase & Loan Details
Income & Expenses
Analysis Results
Monthly Mortgage (P&I):
$0.00
Total Monthly Expenses:
$0.00
Net Operating Income (NOI – Monthly):
$0.00
Monthly Cash Flow:
$0.00
Return on Investment Metrics
Cap Rate:
0.00%
Cash on Cash Return:
0.00%
How to Analyze a Rental Property Investment
Investing in real estate is a numbers game. To ensure a property is a viable asset, investors must calculate the Cash Flow—the net amount of money moving in or out of the investment each month. A positive cash flow means the property generates income after all expenses are paid, while a negative cash flow implies a monthly loss.
Key Metrics Explained
- Cash Flow: This is your bottom line. It is calculated as Gross Rental Income – Total Expenses (Mortgage, Taxes, Insurance, Maintenance, etc.).
- Cap Rate (Capitalization Rate): A measure of the property's natural rate of return, independent of debt. It is calculated as (Net Operating Income / Purchase Price) × 100. A higher Cap Rate generally indicates a better return, though often with higher risk.
- Cash on Cash Return (CoC): This metric compares the annual cash flow to the actual cash you invested (Down Payment). It tells you how hard your money is working.
- The 1% Rule: A quick "rule of thumb" used by investors. It suggests that for a property to cash flow, the monthly rent should be at least 1% of the purchase price. For example, a $200,000 home should rent for at least $2,000.
Common Expense Pitfalls
Many new investors underestimate expenses. This calculator includes fields for Vacancy (money lost when the unit is empty), Management Fees (cost to hire a property manager), and Repairs/CapEx (saving for future roof replacements, HVAC repairs, etc.). Ignoring these can turn a seemingly profitable deal into a liability.
Use this calculator to run scenarios on potential deals. Try adjusting the Purchase Price or Down Payment to see how it affects your Cash on Cash Return.