Analyze the profitability, NOI, and Cash-on-Cash Return of your real estate investment.
Purchase Information
Rental Income
Operating Expenses
Analysis Results
Monthly Mortgage Payment (P&I):$0.00
Total Monthly Expenses (w/ Mortgage):$0.00
Net Operating Income (NOI) / Month:$0.00
Monthly Cash Flow:$0.00
Annual Cash Flow:$0.00
Cap Rate:0.00%
Cash on Cash Return (ROI):0.00%
function calculateRentalROI() {
// 1. Get Input Values
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 years = parseFloat(document.getElementById('loanTerm').value) || 0;
var closingCosts = parseFloat(document.getElementById('closingCosts').value) || 0;
var monthlyRent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var annualTax = parseFloat(document.getElementById('propertyTax').value) || 0;
var annualInsurance = parseFloat(document.getElementById('insurance').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('hoa').value) || 0;
var maintenancePercent = parseFloat(document.getElementById('maintenance').value) || 0;
var managementPercent = parseFloat(document.getElementById('managementFee').value) || 0;
// 2. Calculate Mortgage (Principal & Interest)
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyInterest = (interestRate / 100) / 12;
var numberOfPayments = years * 12;
var mortgagePayment = 0;
if (interestRate === 0) {
mortgagePayment = loanAmount / numberOfPayments;
} else {
mortgagePayment = loanAmount * (monthlyInterest * Math.pow(1 + monthlyInterest, numberOfPayments)) / (Math.pow(1 + monthlyInterest, numberOfPayments) – 1);
}
if (isNaN(mortgagePayment) || !isFinite(mortgagePayment)) mortgagePayment = 0;
// 3. Calculate Monthly Expenses
var monthlyTax = annualTax / 12;
var monthlyInsurance = annualInsurance / 12;
var vacancyCost = monthlyRent * (vacancyRate / 100);
var maintenanceCost = monthlyRent * (maintenancePercent / 100);
var managementCost = monthlyRent * (managementPercent / 100);
var totalOperatingExpenses = monthlyTax + monthlyInsurance + monthlyHOA + vacancyCost + maintenanceCost + managementCost;
var totalExpensesWithMortgage = totalOperatingExpenses + mortgagePayment;
// 4. Calculate Income Metrics
var effectiveGrossIncome = monthlyRent – vacancyCost; // Often vacancy is treated as an expense, but NOI calc subtracts it from Gross Potential Income
// For this display, we'll keep it simple: Income = Rent, Vacancy is an expense line item implicitly in NOI
// Standard NOI = (Gross Income – Vacancy) – Operating Expenses (excluding financing)
var noiMonthly = (monthlyRent – vacancyCost) – (monthlyTax + monthlyInsurance + monthlyHOA + maintenanceCost + managementCost);
var noiAnnual = noiMonthly * 12;
// Cash Flow
var monthlyCashFlow = noiMonthly – mortgagePayment;
var annualCashFlow = monthlyCashFlow * 12;
// Returns
var totalInitialInvestment = downPaymentAmount + closingCosts;
var capRate = (price > 0) ? (noiAnnual / price) * 100 : 0;
var cashOnCash = (totalInitialInvestment > 0) ? (annualCashFlow / totalInitialInvestment) * 100 : 0;
// 5. Update UI
document.getElementById('res-mortgage').innerText = formatCurrency(mortgagePayment);
document.getElementById('res-total-expenses').innerText = formatCurrency(totalExpensesWithMortgage);
document.getElementById('res-noi').innerText = formatCurrency(noiMonthly);
var cashFlowEl = document.getElementById('res-cashflow');
cashFlowEl.innerText = formatCurrency(monthlyCashFlow);
if (monthlyCashFlow < 0) {
cashFlowEl.classList.add('negative-cashflow');
cashFlowEl.classList.remove('highlight-result');
} else {
cashFlowEl.classList.remove('negative-cashflow');
cashFlowEl.classList.add('highlight-result');
}
document.getElementById('res-annual-cashflow').innerText = formatCurrency(annualCashFlow);
document.getElementById('res-cap-rate').innerText = capRate.toFixed(2) + "%";
document.getElementById('res-coc').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('calc-results').style.display = 'block';
}
function formatCurrency(num) {
return '$' + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
Understanding Rental Property Cash Flow Analysis
Investing in real estate is one of the most reliable ways to build wealth, but the difference between a successful investment and a financial burden lies in the numbers. This Rental Property Cash Flow Calculator helps investors determine the viability of a potential purchase by breaking down income, operating expenses, and financing costs.
What is Net Operating Income (NOI)?
Net Operating Income (NOI) is a critical metric calculated by subtracting all operating expenses from the revenue generated by the property. Note that NOI excludes mortgage payments and interest. It strictly measures the profitability of the property itself, regardless of how it is financed.
Formula: NOI = (Gross Rental Income – Vacancy Losses) – Operating Expenses
Cash Flow vs. Cash-on-Cash Return
While NOI tells you how the property performs, Cash Flow tells you what ends up in your pocket every month. It is calculated by subtracting your debt service (mortgage payment) from the NOI.
Positive Cash Flow: The property generates more income than it costs to own.
Negative Cash Flow: You must contribute personal funds monthly to keep the property running.
Cash-on-Cash Return (CoC) measures the annual return on the actual cash you invested (down payment + closing costs). It is often considered the most important metric for investors because it compares the profit to the specific amount of money locked in the deal. A healthy CoC return often ranges between 8% to 12% depending on the market.
How to Use This Calculator
Purchase Information: Enter the price of the home and your loan details. Don't forget closing costs, which affect your initial cash investment.
Income: Input the expected monthly rent. Be realistic—check comparable rentals (comps) in the area.
Expenses: This is where most beginners make mistakes. Ensure you account for vacancy (typically 5-8%), maintenance (5-10%), and Property Management fees (8-10%) if you aren't managing it yourself.
Example Scenario
Imagine purchasing a property for $200,000 with a 20% down payment ($40,000). If the property rents for $1,800/month, and your total expenses (mortgage + taxes + insurance + reserves) come to $1,500/month, your monthly cash flow is $300.
Using this calculator allows you to stress-test your deal: What happens if vacancy rises to 10%? What if interest rates go up by 1%? Adjust the inputs above to see how sensitive your investment is to market changes.