Rental Property Cash Flow Calculator
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Rental Property Cash Flow Calculator
Monthly Principal & Interest:
$0.00
Monthly Operating Expenses:
$0.00
Net Monthly Cash Flow:
$0.00
function calculateRentalCashFlow() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('rp_price').value);
var downPercent = parseFloat(document.getElementById('rp_down').value);
var rate = parseFloat(document.getElementById('rp_rate').value);
var term = parseFloat(document.getElementById('rp_term').value);
var rent = parseFloat(document.getElementById('rp_rent').value);
var tax = parseFloat(document.getElementById('rp_tax').value);
var insurance = parseFloat(document.getElementById('rp_insurance').value);
var hoa = parseFloat(document.getElementById('rp_hoa').value);
var vacancyPercent = parseFloat(document.getElementById('rp_vacancy').value);
var capexPercent = parseFloat(document.getElementById('rp_capex').value);
// Validation
if (isNaN(price) || isNaN(rent) || isNaN(rate) || isNaN(term)) {
alert("Please enter valid numbers for all fields.");
return;
}
// 2. Calculate Mortgage
var loanAmount = price – (price * (downPercent / 100));
var monthlyRate = (rate / 100) / 12;
var numPayments = term * 12;
var mortgagePayment = 0;
if (rate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
} else {
mortgagePayment = loanAmount / numPayments;
}
// 3. Calculate Monthly Expenses
var monthlyTax = tax / 12;
var monthlyInsurance = insurance / 12;
var monthlyVacancy = rent * (vacancyPercent / 100);
var monthlyCapex = rent * (capexPercent / 100);
var totalMonthlyExpenses = monthlyTax + monthlyInsurance + hoa + monthlyVacancy + monthlyCapex;
var totalMonthlyOutflow = mortgagePayment + totalMonthlyExpenses;
// 4. Calculate Metrics
var monthlyCashFlow = rent – totalMonthlyOutflow;
var annualCashFlow = monthlyCashFlow * 12;
// Net Operating Income (NOI) = Income – Operating Expenses (Excluding Mortgage)
var annualNOI = (rent * 12) – (totalMonthlyExpenses * 12);
// Cap Rate = NOI / Price
var capRate = (annualNOI / price) * 100;
// Cash on Cash Return
// Initial Investment = Down Payment + Closing Costs (Assume 3% of price as closing estimate)
var closingCosts = price * 0.03;
var initialInvestment = (price * (downPercent / 100)) + closingCosts;
var cashOnCash = (annualCashFlow / initialInvestment) * 100;
// 5. Update UI
document.getElementById('rp_result_section').style.display = 'block';
document.getElementById('res_mortgage').innerText = "$" + mortgagePayment.toFixed(2);
document.getElementById('res_expenses').innerText = "$" + totalMonthlyExpenses.toFixed(2);
var cashFlowEl = document.getElementById('res_cashflow');
cashFlowEl.innerText = "$" + monthlyCashFlow.toFixed(2);
if (monthlyCashFlow < 0) {
cashFlowEl.classList.add('negative');
cashFlowEl.style.color = '#c0392b';
} else {
cashFlowEl.classList.remove('negative');
cashFlowEl.style.color = '#27ae60';
}
document.getElementById('res_coc').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('res_caprate').innerText = capRate.toFixed(2) + "%";
document.getElementById('res_noi').innerText = "$" + annualNOI.toFixed(2);
}
How to Analyze a Rental Property Investment
Investing in real estate is one of the most reliable ways to build wealth, but it requires careful analysis to ensure profitability. This Rental Property Cash Flow Calculator helps you evaluate potential investment properties by breaking down income, expenses, and key return on investment (ROI) metrics.
Understanding the Key Metrics
When analyzing a rental property, focusing solely on the monthly rent versus the mortgage payment is a common mistake. Professional investors look at three primary metrics:
- Cash Flow: This is the net profit you pocket every month after paying all expenses, including the mortgage, taxes, insurance, and set-aside funds for vacancies and repairs. Positive cash flow is essential for a sustainable investment.
- Cap Rate (Capitalization Rate): Calculated as
Net Operating Income / Purchase Price. This metric measures the property's natural rate of return, independent of how you finance it. It allows you to compare the profitability of different properties directly.
- Cash-on-Cash Return: This measures the return on the actual cash you invested (down payment + closing costs). It is calculated as
Annual Cash Flow / Total Cash Invested. This is often the most important metric for investors using leverage (mortgages).
How to Use This Calculator
To get an accurate result, you need to input realistic data. Here is a breakdown of the fields:
- Vacancy Rate: No property is occupied 100% of the time. A standard conservative estimate is 5% to 8% (about 2-4 weeks per year).
- Repairs & CapEx: Even if the house is new, things break. Budgeting 5% to 10% of the rent for repairs ensures you have funds available when a water heater breaks or the roof needs replacing.
- HOA Fees: If the property is in a Homeowners Association, don't forget to include these monthly dues as they directly reduce your cash flow.
What is a "Good" Return?
While every investor has different goals, many aim for a Cash-on-Cash return of 8-12% or higher. Additionally, a positive monthly cash flow of at least $100-$200 per door is often considered a minimum threshold to ensure the property doesn't become a financial burden during lean months.
Use this tool to experiment with different scenarios—such as a higher down payment or lower rent—to see how sensitive your investment is to market changes.