Total Monthly Expenses (incl. Mortgage/Reserves):$0.00
Monthly Cash Flow:$0.00
Net Operating Income (Annual NOI):$0.00
Cash on Cash ROI:0.00%
Cap Rate:0.00%
function calculateRentalROI() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var termYears = parseFloat(document.getElementById('loanTerm').value) || 0;
var closingCosts = parseFloat(document.getElementById('closingCosts').value) || 0;
var repairCosts = parseFloat(document.getElementById('repairCosts').value) || 0;
var monthlyRent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var annualTaxes = parseFloat(document.getElementById('annualTaxes').value) || 0;
var annualInsurance = parseFloat(document.getElementById('annualInsurance').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('monthlyHOA').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var maintenanceRate = parseFloat(document.getElementById('maintenanceRate').value) || 0;
// 2. Calculate Upfront Costs
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var totalInvested = downPaymentAmount + closingCosts + repairCosts;
// 3. Calculate Mortgage
var monthlyMortgage = 0;
if (loanAmount > 0 && termYears > 0) {
if (interestRate > 0) {
var monthlyRate = (interestRate / 100) / 12;
var numPayments = termYears * 12;
monthlyMortgage = (loanAmount * monthlyRate) / (1 – Math.pow(1 + monthlyRate, -numPayments));
} else {
monthlyMortgage = loanAmount / (termYears * 12);
}
}
// 4. Calculate Operating Expenses
var monthlyTaxes = annualTaxes / 12;
var monthlyInsurance = annualInsurance / 12;
var monthlyVacancyCost = monthlyRent * (vacancyRate / 100);
var monthlyMaintenanceCost = monthlyRent * (maintenanceRate / 100);
// Operating expenses do NOT include mortgage
var monthlyOperatingExpenses = monthlyTaxes + monthlyInsurance + monthlyHOA + monthlyVacancyCost + monthlyMaintenanceCost;
// Total expenses DO include mortgage
var totalMonthlyExpenses = monthlyOperatingExpenses + monthlyMortgage;
// 5. Calculate Metrics
var monthlyCashFlow = monthlyRent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// Net Operating Income (Annual) = (Income – Operating Expenses) * 12
var annualNOI = (monthlyRent – monthlyOperatingExpenses) * 12;
// Cash on Cash ROI = (Annual Cash Flow / Total Invested) * 100
var cocROI = 0;
if (totalInvested > 0) {
cocROI = (annualCashFlow / totalInvested) * 100;
}
// Cap Rate = (Annual NOI / Purchase Price) * 100
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// 6. Formatter
var formatCurrency = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
// 7. Update UI
document.getElementById('displayTotalInvested').innerText = formatCurrency.format(totalInvested);
document.getElementById('displayMortgage').innerText = formatCurrency.format(monthlyMortgage);
document.getElementById('displayTotalExpenses').innerText = formatCurrency.format(totalMonthlyExpenses);
var cfElement = document.getElementById('displayCashFlow');
cfElement.innerText = formatCurrency.format(monthlyCashFlow);
if(monthlyCashFlow >= 0) {
cfElement.classList.remove('negative');
cfElement.classList.add('positive');
} else {
cfElement.classList.remove('positive');
cfElement.classList.add('negative');
}
document.getElementById('displayNOI').innerText = formatCurrency.format(annualNOI);
var cocElement = document.getElementById('displayCOC');
cocElement.innerText = cocROI.toFixed(2) + '%';
if(cocROI >= 0) {
cocElement.classList.remove('negative');
cocElement.classList.add('positive');
} else {
cocElement.classList.remove('positive');
cocElement.classList.add('negative');
}
document.getElementById('displayCapRate').innerText = capRate.toFixed(2) + '%';
document.getElementById('resultArea').style.display = 'block';
}
How to Analyze Rental Properties for Maximum ROI
Investing in real estate is one of the most reliable ways to build wealth, but simply buying a property and renting it out doesn't guarantee a profit. To succeed, you must understand the numbers behind the deal. This guide explains how to use our Rental Property ROI Calculator to analyze potential investments effectively.
1. Understanding Cash Flow
Cash Flow is the profit you bring in each month after all expenses are paid. It is calculated as:
Cash Flow = Total Monthly Income – Total Monthly Expenses
Income usually comes from rent, but expenses include more than just the mortgage. You must account for taxes, insurance, HOA fees, and hidden costs like vacancy and maintenance reserves. A positive cash flow ensures the property pays for itself and puts money in your pocket.
2. Cash on Cash ROI (CoC)
This is arguably the most important metric for rental investors. It measures the annual return on the actual cash you invested, not the total loan amount.
CoC ROI = (Annual Cash Flow / Total Cash Invested) × 100
For example, if you invest $50,000 (down payment + closing costs) and the property generates $5,000 in positive cash flow per year, your Cash on Cash ROI is 10%. This allows you to compare real estate returns directly against other investments like stocks or bonds.
3. Cap Rate (Capitalization Rate)
The Cap Rate helps you evaluate a property's profitability regardless of how you finance it (cash vs. loan). It measures the property's natural rate of return.
Cap Rate = (Net Operating Income / Purchase Price) × 100
Net Operating Income (NOI) is your income minus operating expenses (excluding mortgage payments). A higher Cap Rate generally indicates a higher potential return, though often associated with higher risk neighborhoods.
Why Include Vacancy and Maintenance?
Novice investors often forget to budget for months when the property sits empty (Vacancy) or when things break (Maintenance). Our calculator allows you to set a percentage of monthly rent aside for these "invisible" costs. A standard safe estimate is 5-8% for vacancy and 5-10% for maintenance depending on the age of the home.
Interpreting Your Results
If your Cash Flow is negative, the property is a liability, costing you money every month. If your Cash on Cash ROI is lower than inflation or safe bond yields (e.g., under 4-5%), the risk of owning the property may not be worth the reward. Most seasoned investors look for a CoC ROI of 8-12% or higher.