Percentage of rent to save for repairs and empty months.
Financial Analysis
Loan Amount:$0.00
Monthly Mortgage P&I:$0.00
Total Monthly Expenses:$0.00
Monthly Cash Flow:$0.00
Cash on Cash Return (ROI):0.00%
function calculateRental() {
// 1. Retrieve Inputs
var price = parseFloat(document.getElementById('propPrice').value);
var downPct = parseFloat(document.getElementById('downPct').value);
var rate = parseFloat(document.getElementById('intRate').value);
var term = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var taxYearly = parseFloat(document.getElementById('propTax').value);
var insYearly = parseFloat(document.getElementById('propIns').value);
var hoa = parseFloat(document.getElementById('hoaFee').value);
var maintPct = parseFloat(document.getElementById('maintPct').value);
// Validation
if (isNaN(price) || isNaN(downPct) || isNaN(rate) || isNaN(term) || isNaN(rent)) {
alert("Please enter valid numbers in all fields.");
return;
}
// 2. Perform Calculations
var downPayment = price * (downPct / 100);
var loanAmount = price – downPayment;
// Mortgage Calculation (M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ])
var monthlyRate = (rate / 100) / 12;
var numPayments = term * 12;
var mortgagePayment = 0;
if (monthlyRate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
} else {
mortgagePayment = loanAmount / numPayments;
}
// Monthly Expenses Breakdown
var taxMonthly = taxYearly / 12;
var insMonthly = insYearly / 12;
var maintCost = rent * (maintPct / 100);
var totalOperatingExpenses = taxMonthly + insMonthly + hoa + maintCost;
var totalExpenses = totalOperatingExpenses + mortgagePayment;
// Cash Flow
var cashFlow = rent – totalExpenses;
var annualCashFlow = cashFlow * 12;
// Cash on Cash Return = Annual Cash Flow / Total Cash Invested
// Simplifying Total Cash Invested to just Down Payment for this tool,
// though in reality it includes closing costs and rehab.
var investedCapital = downPayment;
var cocReturn = 0;
if (investedCapital > 0) {
cocReturn = (annualCashFlow / investedCapital) * 100;
}
// 3. Update DOM
document.getElementById('resLoanAmount').innerHTML = "$" + loanAmount.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resMortgage').innerHTML = "$" + mortgagePayment.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resExpenses').innerHTML = "$" + totalExpenses.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
var cfElement = document.getElementById('resCashFlow');
cfElement.innerHTML = "$" + cashFlow.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
if (cashFlow >= 0) {
cfElement.className = "result-value positive-cf";
} else {
cfElement.className = "result-value negative-cf";
}
document.getElementById('resCoc').innerHTML = cocReturn.toFixed(2) + "%";
// Show results container
document.getElementById('resultBox').style.display = "block";
}
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but not every property is a good deal. To ensure your investment is profitable, you must accurately calculate your Cash Flow and Cash on Cash Return. This calculator helps investors analyze the potential profitability of a rental property before signing on the dotted line.
What is Cash Flow?
Cash flow is the net amount of cash moving into and out of a business. In real estate, it is calculated as: Total Rental Income – Total Expenses (Mortgage + Taxes + Insurance + Maintenance) = Net Cash Flow
Key Metrics Explained
1. Monthly Mortgage P&I
This is your principal and interest payment to the lender. It is the largest expense for most leveraged real estate deals. Our calculator uses standard amortization formulas to determine this cost based on your interest rate and loan term.
2. Operating Expenses (OpEx)
Many new investors make the mistake of only counting the mortgage. A true analysis must include:
Property Taxes: Paid to the local government, usually based on assessed value.
Insurance: Landlord insurance policies protect your asset.
HOA Fees: Homeowners Association fees if the property is in a managed community/condo.
Maintenance & Vacancy: You should always set aside a percentage (usually 5-10% each) of the rent for repairs and months where the property sits empty.
3. Cash on Cash Return (CoC)
This is arguably the most important metric for ROI. It measures the annual return made on the property in relation to the amount of mortgage paid during the same year.
For example, if you put down $50,000 to buy a house and it generates $5,000 in positive cash flow per year, your Cash on Cash return is:
$5,000 / $50,000 = 10% Return
What is a Good ROI for Rental Property?
While answers vary depending on the market and strategy, many investors look for the following benchmarks:
Cash Flow: $100 – $300 per door, per month is often considered a minimum safe margin.
Cash on Cash Return: 8% to 12% is considered good, while 15%+ is considered excellent in most markets.
How to Use This Calculator
Simply input the purchase price of the target property, your financing details (down payment and interest rate), and the expected operational costs. Be conservative with your rental income estimates and generous with your expense estimates to ensure a "safe" analysis. If the numbers work with conservative estimates, the deal is likely a winner.