Analyze the profitability and ROI of your real estate investments instantly.
Purchase Information
Financing Details
Income & Expenses (Monthly)
Monthly Principal & Interest:$0.00
Total Monthly Cash Outflow:$0.00
Net Operating Income (Annual):$0.00
Monthly Cash Flow:$0.00
Cash on Cash ROI:0.00%
Cap Rate:0.00%
function calculateRentalRoi() {
// 1. Get Inputs
var price = parseFloat(document.getElementById("purchasePrice").value);
var closing = parseFloat(document.getElementById("closingCosts").value);
var downPercent = parseFloat(document.getElementById("downPaymentPercent").value);
var rate = parseFloat(document.getElementById("interestRate").value);
var term = parseFloat(document.getElementById("loanTerm").value);
var rent = parseFloat(document.getElementById("monthlyRent").value);
var expenses = parseFloat(document.getElementById("monthlyExpenses").value);
// Validation: Ensure all fields are numbers
if (isNaN(price) || isNaN(closing) || isNaN(downPercent) || isNaN(rate) || isNaN(term) || isNaN(rent) || isNaN(expenses)) {
alert("Please fill in all fields with valid numbers.");
return;
}
// 2. Loan Calculations
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (rate / 100) / 12;
var numPayments = term * 12;
// Mortgage Calculation Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var monthlyMortgage = 0;
if (rate === 0) {
monthlyMortgage = loanAmount / numPayments;
} else {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
}
// 3. Cash Flow Calculations
var totalMonthlyOutflow = monthlyMortgage + expenses;
var monthlyCashFlow = rent – totalMonthlyOutflow;
var annualCashFlow = monthlyCashFlow * 12;
// 4. ROI Metrics
var totalInitialInvestment = downPaymentAmount + closing;
// Net Operating Income (NOI) = (Annual Rent – Annual OpEx) *excludes mortgage*
var annualNOI = (rent – expenses) * 12;
// Cash on Cash ROI = (Annual Cash Flow / Total Cash Invested) * 100
var cocRoi = 0;
if (totalInitialInvestment > 0) {
cocRoi = (annualCashFlow / totalInitialInvestment) * 100;
}
// Cap Rate = (NOI / Purchase Price) * 100
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// 5. Display Results
document.getElementById("calc-results").style.display = "block";
// Formatting Helpers
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
document.getElementById("resultMortgage").innerText = formatter.format(monthlyMortgage);
document.getElementById("resultOutflow").innerText = formatter.format(totalMonthlyOutflow);
document.getElementById("resultNOI").innerText = formatter.format(annualNOI);
var cashFlowEl = document.getElementById("resultCashFlow");
cashFlowEl.innerText = formatter.format(monthlyCashFlow);
if (monthlyCashFlow >= 0) {
cashFlowEl.className = "result-value big-result highlight-positive";
} else {
cashFlowEl.className = "result-value big-result highlight-negative";
}
var cocEl = document.getElementById("resultCOC");
cocEl.innerText = cocRoi.toFixed(2) + "%";
if (cocRoi >= 0) {
cocEl.className = "result-value big-result highlight-positive";
} else {
cocEl.className = "result-value big-result highlight-negative";
}
document.getElementById("resultCapRate").innerText = capRate.toFixed(2) + "%";
}
Understanding Real Estate Investment Analysis
Investing in rental properties is one of the most powerful ways to build wealth, but simply buying a property doesn't guarantee a profit. Successful real estate investors rely on accurate data to determine if a deal makes sense financially. This Rental Property Cash Flow Calculator helps you evaluate the two most critical metrics in real estate: Monthly Cash Flow and Cash on Cash Return on Investment (ROI).
What is Monthly Cash Flow?
Monthly Cash Flow is the net profit you pocket every month after all expenses are paid. It is calculated by taking your total monthly rental income and subtracting your total monthly expenses, including the mortgage payment, property taxes, insurance, HOA fees, and maintenance costs.
Positive Cash Flow means the property is generating income for you. Negative Cash Flow means you are losing money every month to hold the property. Most investors aim for at least $100–$300 per door in positive cash flow.
Understanding Cash on Cash ROI
While Cash Flow tells you how much money you make monthly, Cash on Cash ROI tells you how hard your money is working for you. It compares your annual profit to the actual cash you invested (Down Payment + Closing Costs).
Formula: (Annual Cash Flow / Total Cash Invested) × 100
Example: If you invest $50,000 to buy a house and it generates $5,000 in profit per year, your Cash on Cash ROI is 10%.
A "good" ROI depends on your goals, but many investors look for returns between 8% and 12%, which typically beats the average stock market return.
What is Cap Rate?
The Capitalization Rate (Cap Rate) measures the natural rate of return of a real estate investment assuming you paid all cash (no mortgage). It helps you compare the profitability of different properties regardless of how they are financed. A higher Cap Rate generally indicates a higher potential return, but often comes with higher risk.
How to Use This Calculator
Purchase Info: Enter the price of the property and estimated closing costs.
Financing: Input your down payment percentage, loan interest rate, and term (usually 30 years).
Income & Expenses: Enter the expected monthly rent and total operating expenses. Don't forget to account for vacancy and repairs in your expense estimates.
Analyze: Click "Calculate Cash Flow" to see if the deal meets your investment criteria.