Rental Property Cash Flow Calculator
/* Calculator Container Styles */
.roi-calculator-wrapper {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 0;
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border-radius: 8px;
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Investment Analysis
Loan Amount:
$200,000
Monthly P&I:
$1,264
Total Monthly Expenses:
$1,765
Net Monthly Cash Flow:
$435
Annual NOI:
$15,800
Cash on Cash Return (CoC):
10.4%
Cap Rate:
6.3%
function calculateROI() {
// 1. Get Values using var
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var downPercent = parseFloat(document.getElementById('downPayment').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var loanYears = parseFloat(document.getElementById('loanTerm').value) || 0;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var taxYearly = parseFloat(document.getElementById('annualTaxes').value) || 0;
var insuranceYearly = parseFloat(document.getElementById('annualInsurance').value) || 0;
var maintenanceMonthly = parseFloat(document.getElementById('maintenance').value) || 0;
var vacancyPercent = parseFloat(document.getElementById('vacancyRate').value) || 0;
// 2. Loan Calculations
var downAmount = price * (downPercent / 100);
var loanAmount = price – downAmount;
// Monthly Interest Rate
var r = (interestRate / 100) / 12;
// Total Payments
var n = loanYears * 12;
// Mortgage P&I Formula: P * (r(1+r)^n) / ((1+r)^n – 1)
var mortgagePayment = 0;
if (loanAmount > 0 && interestRate > 0) {
mortgagePayment = loanAmount * (r * Math.pow(1 + r, n)) / (Math.pow(1 + r, n) – 1);
} else if (loanAmount > 0 && interestRate === 0) {
mortgagePayment = loanAmount / n;
}
// 3. Expenses Calculations
var taxMonthly = taxYearly / 12;
var insuranceMonthly = insuranceYearly / 12;
var vacancyMonthly = rent * (vacancyPercent / 100);
var totalOperatingExpenses = taxMonthly + insuranceMonthly + maintenanceMonthly + vacancyMonthly;
var totalMonthlyCost = totalOperatingExpenses + mortgagePayment;
// 4. Metrics
var monthlyCashFlow = rent – totalMonthlyCost;
var annualCashFlow = monthlyCashFlow * 12;
// Net Operating Income (NOI) = Income – Operating Expenses (Excluding Debt Service)
var monthlyNOI = rent – totalOperatingExpenses;
var annualNOI = monthlyNOI * 12;
// Cash on Cash Return = Annual Cash Flow / Total Cash Invested (Down Payment)
// Note: For simplicity, closing costs are ignored here unless added to input, using Down Payment as Cash Invested
var cocReturn = 0;
if (downAmount > 0) {
cocReturn = (annualCashFlow / downAmount) * 100;
} else if (price > 0 && downAmount === 0) {
// Infinite return if no money down, technically
cocReturn = 0;
}
// Cap Rate = NOI / Purchase Price
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// 5. Update UI
// Format Currency Function
var fmt = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD', minimumFractionDigits: 0, maximumFractionDigits: 0 });
document.getElementById('resLoanAmount').innerHTML = fmt.format(loanAmount);
document.getElementById('resMortgage').innerHTML = fmt.format(mortgagePayment);
document.getElementById('resTotalExpenses').innerHTML = fmt.format(totalMonthlyCost);
var cfEl = document.getElementById('resCashFlow');
cfEl.innerHTML = fmt.format(monthlyCashFlow);
cfEl.style.color = monthlyCashFlow >= 0 ? '#27ae60' : '#c0392b';
document.getElementById('resNOI').innerHTML = fmt.format(annualNOI);
document.getElementById('resCoC').innerHTML = cocReturn.toFixed(2) + "%";
document.getElementById('resCapRate').innerHTML = capRate.toFixed(2) + "%";
}
// Initialize on load
window.onload = function() {
calculateROI();
};
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but not every property is a good deal. The difference between a profitable investment and a financial burden often comes down to the numbers. This Rental Property Cash Flow Calculator is designed to help investors analyze deals quickly and accurately.
What is Cash Flow?
Cash flow is the profit remaining after all expenses are paid. It is calculated by taking your gross monthly rent and subtracting every cost associated with the property, including the mortgage, property taxes, insurance, maintenance, and vacancy allowances. A positive cash flow means the property is putting money in your pocket every month.
Key Metrics Explained
- Net Operating Income (NOI): This is the annual income generated by the property after deducting operating expenses but before deducting mortgage payments. It is a raw measure of the property's profitability.
- Cap Rate (Capitalization Rate): Calculated as
NOI / Purchase Price. This metric helps you compare the return of different properties regardless of how they are financed. A higher Cap Rate generally indicates a better return, though often with higher risk.
- Cash on Cash Return (CoC): Calculated as
Annual Cash Flow / Total Cash Invested. This is arguably the most important metric for investors using leverage (mortgages), as it tells you the percentage return on the actual cash you put into the deal (down payment).
How to Use This Calculator
Start by entering the Purchase Price and your financing details. Be honest with your expense estimates. New investors often overlook Vacancy Rates (the time the property sits empty) and Maintenance Reserves (saving for future repairs like a new roof or water heater). A common rule of thumb is to set aside 5-10% of rent for maintenance and 5-8% for vacancy.
Why is a Negative Cash Flow Dangerous?
If the result shows a negative cash flow, you are effectively paying monthly to own the property. While some investors accept this banking on future appreciation, it is a risky strategy. Positive cash flow ensures the property sustains itself during market downturns.
What is a good Cash on Cash return?
While targets vary by investor and market, a Cash on Cash return of 8% to 12% is generally considered solid for rental properties. Some aggressive investors look for 15%+, while those in high-appreciation markets might accept 4-6%.
Should I include the mortgage in NOI calculations?
No. Net Operating Income (NOI) strictly measures the property's ability to generate revenue compared to its operating expenses. It excludes debt service (mortgage principal and interest). If you include the mortgage, you are calculating Cash Flow, not NOI.