Analyze cash flow, Cap Rate, and ROI for real estate investments.
Purchase & Loan Details
30 Years
15 Years
10 Years
Income & Recurring Expenses
Variable Expenses
Monthly Cash Flow
$0.00
Cash on Cash ROI
0.00%
Cap Rate
0.00%
Total Cash Needed
$0.00
Monthly Breakdown
Gross Rental Income
$0.00
Mortgage Payment (P&I)
$0.00
Property Tax
$0.00
Insurance
$0.00
HOA / Misc
$0.00
Maintenance (Est.)
$0.00
Vacancy (Est.)
$0.00
Total Monthly Expenses
$0.00
Understanding Rental Property Cash Flow Analysis
Investing in real estate is one of the most powerful ways to build wealth, but it requires precise calculations to ensure profitability. A Rental Property Calculator is an essential tool for investors to evaluate a potential deal before signing a contract. It helps determine if a property will generate positive cash flow or become a financial liability.
What is Cash Flow?
Cash flow is the net amount of money moving in and out of a rental property business. In simple terms, it is your total income minus your total expenses.
Positive Cash Flow: The property generates more money than it costs to own and operate. This is the goal for most buy-and-hold investors.
Negative Cash Flow: The property costs more to maintain than it brings in rent. This might be acceptable if the primary goal is appreciation, but it carries higher risk.
Key Metrics Explained
When analyzing a rental property, you shouldn't rely on just one number. This calculator provides three critical metrics:
1. Cash on Cash Return (CoC ROI)
This metric measures the annual return on the actual cash you invested (down payment + closing costs + rehab costs). Unlike standard ROI, which might look at the total loan value, CoC ROI tells you how hard your specific dollars are working.
Formula: Annual Cash Flow / Total Cash Invested
2. Cap Rate (Capitalization Rate)
The Cap Rate measures the natural rate of return of the property assuming you paid all cash (no mortgage). It is excellent for comparing the profitability of different properties regardless of financing.
Formula: Net Operating Income (NOI) / Purchase Price
3. Net Operating Income (NOI)
NOI is the total income the property generates minus all necessary operating expenses (taxes, insurance, maintenance, vacancy) but excluding mortgage payments. Lenders look at NOI to determine if a property generates enough income to cover the debt.
Estimating Expenses Accurately
The most common mistake new investors make is underestimating expenses. Always account for:
Vacancy Rate: Properties won't be rented 365 days a year. A 5-8% vacancy allowance is standard.
Maintenance: Even new homes break. Set aside 5-10% of monthly rent for future repairs (HVAC, roof, plumbing).
Property Management: If you hire a manager, expect to pay 8-10% of the monthly rent.
How to Use This Calculator
Enter your purchase price and financing details to determine your mortgage payment. Then, input your estimated rental income and itemized expenses. The calculator will automatically deduct "hidden" costs like vacancy and maintenance reserves to give you a realistic picture of your monthly profit.
function calculateRental() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('rpc_price').value);
var downPercent = parseFloat(document.getElementById('rpc_down_percent').value);
var rate = parseFloat(document.getElementById('rpc_rate').value);
var term = parseFloat(document.getElementById('rpc_term').value);
var rent = parseFloat(document.getElementById('rpc_rent').value);
var taxYearly = parseFloat(document.getElementById('rpc_tax').value);
var insuranceYearly = parseFloat(document.getElementById('rpc_insurance').value);
var hoaMonthly = parseFloat(document.getElementById('rpc_hoa').value);
var repairPercent = parseFloat(document.getElementById('rpc_repair').value);
var vacancyPercent = parseFloat(document.getElementById('rpc_vacancy').value);
// Validation
if (isNaN(price) || isNaN(rent) || isNaN(rate) || price 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, totalPayments)) / (Math.pow(1 + monthlyRate, totalPayments) – 1);
} else {
mortgagePayment = loanAmount / totalPayments;
}
// 3. Expense Calculations
var taxMonthly = taxYearly / 12;
var insuranceMonthly = insuranceYearly / 12;
var repairMonthly = rent * (repairPercent / 100);
var vacancyMonthly = rent * (vacancyPercent / 100);
var totalOperatingExpenses = taxMonthly + insuranceMonthly + hoaMonthly + repairMonthly + vacancyMonthly;
var totalExpenses = totalOperatingExpenses + mortgagePayment;
// 4. Profitability Metrics
var cashFlowMonthly = rent – totalExpenses;
var cashFlowYearly = cashFlowMonthly * 12;
// Net Operating Income (NOI) = Income – Operating Expenses (Excluding Mortgage)
var noiMonthly = rent – totalOperatingExpenses;
var noiYearly = noiMonthly * 12;
// Cap Rate = (Annual NOI / Purchase Price) * 100
var capRate = (noiYearly / price) * 100;
// Cash on Cash ROI = (Annual Cash Flow / Total Cash Invested) * 100
// Total Cash Invested approx = Down Payment (simplification, usually includes closing costs)
var cashInvested = downPayment;
var cocRoi = 0;
if (cashInvested > 0) {
cocRoi = (cashFlowYearly / cashInvested) * 100;
}
// 5. Update UI
// Helper for currency
var fmt = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
document.getElementById('res_cashflow').innerText = fmt.format(cashFlowMonthly);
document.getElementById('res_cashflow').className = "value " + (cashFlowMonthly >= 0 ? "positive" : "negative");
document.getElementById('res_coc').innerText = cocRoi.toFixed(2) + "%";
document.getElementById('res_coc').className = "value " + (cocRoi >= 0 ? "positive" : "negative");
document.getElementById('res_cap').innerText = capRate.toFixed(2) + "%";
document.getElementById('res_investment').innerText = fmt.format(cashInvested);
// Breakdown Table
document.getElementById('bd_income').innerText = fmt.format(rent);
document.getElementById('bd_mortgage').innerText = fmt.format(mortgagePayment);
document.getElementById('bd_tax').innerText = fmt.format(taxMonthly);
document.getElementById('bd_insurance').innerText = fmt.format(insuranceMonthly);
document.getElementById('bd_hoa').innerText = fmt.format(hoaMonthly);
document.getElementById('bd_maint').innerText = fmt.format(repairMonthly);
document.getElementById('bd_vacancy').innerText = fmt.format(vacancyMonthly);
document.getElementById('bd_total_exp').innerText = fmt.format(totalExpenses);
// Show Results Area
document.getElementById('rpc_results_area').style.display = "block";
}