Analyze your real estate investment potential instantly.
Analysis Results
Monthly Principal & Interest:$0.00
Total Monthly Expenses:$0.00
Net Operating Income (Monthly):$0.00
Monthly Cash Flow:$0.00
Annual Cash Flow:$0.00
Cash on Cash Return:0.00%
Cap Rate:0.00%
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but the success of any rental property hinges on the numbers. This Rental Property Cash Flow Calculator helps investors determine if a property will be an asset (generating positive income) or a liability (costing money every month).
How to Use This Calculator
To get an accurate analysis, you will need to input four main categories of data:
Purchase Information: The total price of the property and your down payment percentage. This determines your loan amount and initial cash investment.
Loan Details: Your interest rate and loan term (usually 30 years). These figures calculate your principal and interest (P&I) payments.
Income: The expected monthly rent. Don't forget to account for vacancy rates, as properties are rarely occupied 100% of the time.
Expenses: Beyond the mortgage, you must account for property taxes, insurance, maintenance reserves, and any HOA fees.
Key Metrics Explained
This calculator provides several critical metrics for real estate investors:
1. Monthly Cash Flow
This is the money left over after all expenses are paid. Formula: Total Income – Total Expenses = Cash Flow. Positive cash flow means the property pays for itself and provides profit.
2. Cash on Cash Return (CoC)
This metric measures the annual return on the actual cash you invested (down payment + closing costs), rather than the total loan amount. It allows you to compare real estate returns against other investment vehicles like stocks.
3. Cap Rate (Capitalization Rate)
Cap Rate measures the property's natural rate of return assuming you bought it with all cash. It is calculated by dividing the Net Operating Income (NOI) by the property asset value. It is useful for comparing the profitability of different properties regardless of financing.
Why Accurate Estimation Matters
Many new investors fail because they underestimate expenses. A common mistake is ignoring maintenance (roofs, HVACs, and water heaters break) or vacancy. A standard rule of thumb is to set aside 5-10% of rent for maintenance and 5% for vacancy. Using this calculator helps you factor in these "hidden" costs to ensure your investment remains profitable in the long run.
function calculateCashFlow() {
// Get Input Values
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPerc = parseFloat(document.getElementById('downPayment').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var termYears = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var vacancyPerc = parseFloat(document.getElementById('vacancyRate').value);
var taxYearly = parseFloat(document.getElementById('propertyTax').value);
var insuranceYearly = parseFloat(document.getElementById('insurance').value);
var maintPerc = parseFloat(document.getElementById('maintenance').value);
var otherMonthly = parseFloat(document.getElementById('otherExpenses').value);
// Validation
if (isNaN(price) || isNaN(downPerc) || isNaN(interestRate) || isNaN(termYears)) {
alert("Please enter valid numbers for the loan details.");
return;
}
// 1. Calculate Loan Payment
var downPaymentAmount = price * (downPerc / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = termYears * 12;
var mortgagePayment = 0;
if (interestRate === 0) {
mortgagePayment = loanAmount / numberOfPayments;
} else {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// 2. Calculate Operating Expenses
var monthlyTax = taxYearly / 12;
var monthlyInsurance = insuranceYearly / 12;
var monthlyVacancy = rent * (vacancyPerc / 100);
var monthlyMaintenance = rent * (maintPerc / 100);
var totalOperatingExpenses = monthlyTax + monthlyInsurance + monthlyVacancy + monthlyMaintenance + otherMonthly;
var totalExpenses = totalOperatingExpenses + mortgagePayment;
// 3. Calculate Metrics
var noi = rent – totalOperatingExpenses – otherMonthly; // NOI usually excludes debt service
// Actually, precise NOI = Income – Operating Expenses. Operating expenses usually include Tax, Ins, Maint, Vacancy, Management.
// It does NOT include Mortgage Interest or Principal.
// Let's refine NOI calculation:
var noiMonthly = (rent – monthlyVacancy) – (monthlyTax + monthlyInsurance + monthlyMaintenance + otherMonthly);
var noiYearly = noiMonthly * 12;
var cashFlowMonthly = noiMonthly – mortgagePayment;
var cashFlowYearly = cashFlowMonthly * 12;
// Cash on Cash Return
// Assuming closing costs are roughly 2% of price for estimation, or just use Down Payment if simple.
// Let's assume just Down Payment to keep it consistent with inputs provided.
var totalCashInvested = downPaymentAmount;
var cashOnCash = 0;
if (totalCashInvested > 0) {
cashOnCash = (cashFlowYearly / totalCashInvested) * 100;
}
// Cap Rate
var capRate = (noiYearly / price) * 100;
// 4. Update UI
// Helper for formatting currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
});
document.getElementById('resMortgage').innerText = formatter.format(mortgagePayment);
document.getElementById('resExpenses').innerText = formatter.format(totalExpenses); // This is Total Monthly Expenses (Ops + Mortgage)
document.getElementById('resNOI').innerText = formatter.format(noiMonthly);
var cfElement = document.getElementById('resCashFlow');
cfElement.innerText = formatter.format(cashFlowMonthly);
// Color coding for Cash Flow
if (cashFlowMonthly >= 0) {
cfElement.className = "result-value positive-cf";
document.getElementById('resAnnualCashFlow').className = "result-value positive-cf";
} else {
cfElement.className = "result-value negative-cf";
document.getElementById('resAnnualCashFlow').className = "result-value negative-cf";
}
document.getElementById('resAnnualCashFlow').innerText = formatter.format(cashFlowYearly);
document.getElementById('resCoC').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
// Show results
document.getElementById('resultsSection').style.display = "block";
}