Analyze the profitability and ROI of your real estate investment.
Purchase Information
Rental Income
Monthly Expenses
Investment Analysis
Monthly Mortgage (P&I):$0.00
Total Monthly Expenses:$0.00
Net Operating Income (NOI):$0.00
Monthly Cash Flow:$0.00
Cash on Cash Return (ROI):0.00%
Cap Rate:0.00%
function calculateRental() {
// 1. Get Input Values
var price = parseFloat(document.getElementById("purchasePrice").value);
var closingCosts = parseFloat(document.getElementById("closingCosts").value);
var dpPercent = parseFloat(document.getElementById("downPaymentPercent").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var years = parseFloat(document.getElementById("loanTerm").value);
var rent = parseFloat(document.getElementById("monthlyRent").value);
var vacancyPercent = parseFloat(document.getElementById("vacancyRate").value);
var annualTax = parseFloat(document.getElementById("propertyTax").value);
var annualIns = parseFloat(document.getElementById("insurance").value);
var monthlyHoa = parseFloat(document.getElementById("hoa").value);
var maintPercent = parseFloat(document.getElementById("maintenance").value);
var mgmtPercent = parseFloat(document.getElementById("managementFee").value);
// Validation
if (isNaN(price) || isNaN(dpPercent) || isNaN(interestRate) || isNaN(years) || isNaN(rent)) {
alert("Please enter valid numbers for all fields.");
return;
}
// 2. Mortgage Calculation
var downPaymentAmount = price * (dpPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = years * 12;
var monthlyMortgage = 0;
if (interestRate === 0) {
monthlyMortgage = loanAmount / numberOfPayments;
} else {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// 3. Income Calculation
var vacancyCost = rent * (vacancyPercent / 100);
var effectiveGrossIncome = rent – vacancyCost;
// 4. Expense Calculation
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var maintenanceCost = rent * (maintPercent / 100);
var managementCost = rent * (mgmtPercent / 100);
var totalMonthlyExpenses = monthlyTax + monthlyIns + monthlyHoa + maintenanceCost + managementCost + vacancyCost;
// Note: Usually vacancy is subtracted from income, but for total expense tracking some list it here.
// Standard definition: NOI = Income – Operating Expenses. Mortgage is NOT an operating expense.
var operatingExpenses = monthlyTax + monthlyIns + monthlyHoa + maintenanceCost + managementCost;
// 5. Net Operating Income (NOI)
var noiMonthly = effectiveGrossIncome – operatingExpenses;
var noiAnnual = noiMonthly * 12;
// 6. Cash Flow Calculation
var monthlyCashFlow = noiMonthly – monthlyMortgage;
var annualCashFlow = monthlyCashFlow * 12;
// 7. ROI Calculations
var totalInitialInvestment = downPaymentAmount + closingCosts;
var cashOnCashReturn = 0;
if (totalInitialInvestment > 0) {
cashOnCashReturn = (annualCashFlow / totalInitialInvestment) * 100;
}
var capRate = (noiAnnual / price) * 100;
// 8. Update UI
document.getElementById("resultsArea").style.display = "block";
document.getElementById("displayMortgage").innerHTML = "$" + monthlyMortgage.toFixed(2);
// Total expenses displayed includes mortgage for the user's "money out" visualization,
// or just operating? Let's show Operating Expenses + Mortgage to show total monthly cost.
var totalCost = operatingExpenses + monthlyMortgage;
document.getElementById("displayTotalExpenses").innerHTML = "$" + totalCost.toFixed(2);
document.getElementById("displayNOI").innerHTML = "$" + noiMonthly.toFixed(2);
var cfElement = document.getElementById("displayCashFlow");
cfElement.innerHTML = "$" + monthlyCashFlow.toFixed(2);
if (monthlyCashFlow >= 0) {
cfElement.className = "result-value positive-cashflow";
} else {
cfElement.className = "result-value negative-cashflow";
}
document.getElementById("displayCOC").innerHTML = cashOnCashReturn.toFixed(2) + "%";
document.getElementById("displayCapRate").innerHTML = capRate.toFixed(2) + "%";
}
Understanding Rental Property Cash Flow
Investing in real estate is a powerful way to build wealth, but simply buying a property and renting it out doesn't guarantee a profit. To succeed, you must accurately calculate your Cash Flow. This calculator helps investors determine if a potential rental property will generate positive income after all expenses and debt service are paid.
What is Cash on Cash Return?
Cash on Cash Return (CoC) is a metric often used in real estate transactions that calculates the cash income earned on the cash invested in a property. Unlike a standard return on investment (ROI) which might consider the total loan value, CoC only looks at the actual liquid capital you put into the deal (Down Payment + Closing Costs).
The Formula: Cash on Cash Return = (Annual Pre-Tax Cash Flow / Total Cash Invested) x 100%
Key Metrics Explained
Net Operating Income (NOI): This is your annual rental income minus all operating expenses (taxes, insurance, maintenance, vacancy) but excluding mortgage payments. It represents the profitability of the property itself.
Cap Rate: The ratio of Net Operating Income to the property asset value. It helps compare the profitability of different properties regardless of how they are financed.
Vacancy Rate: No property is rented 100% of the time. A prudent investor budgets 5-10% for vacancy to avoid cash flow surprises during turnover periods.
How to Use This Calculator
Enter Purchase Details: Input the property price, your down payment percentage, and loan details. Don't forget closing costs, which usually range from 2-5% of the purchase price.
Estimate Income: Enter the expected monthly rent. Check comparable listings in the neighborhood (comps) to ensure your number is realistic.
Account for Expenses: Be honest about expenses. Include property taxes, insurance, and set aside funds for maintenance (typically 5-10% of rent) and capital expenditures (roof, HVAC).
Example Scenario
Imagine you buy a property for $200,000 with 20% down ($40,000). Your mortgage is roughly $1,000/month. You rent it for $1,800/month. After taxes, insurance, and maintenance, your operating expenses are $500/month.
Your NOI is $1,300 ($1,800 – $500). Your cash flow is $300 ($1,300 – $1,000). While $300 seems low, annually that is $3,600. Divided by your $40,000 investment, that is a 9% Cash on Cash Return, which is a solid benchmark for many investors.