Please fill in all required fields with valid numbers.
Monthly Mortgage (P&I):$0.00
Total Monthly Expenses:$0.00
Net Operating Income (Monthly):$0.00
Monthly Cash Flow:$0.00
Cash on Cash Return:0.00%
Cap Rate:0.00%
function calculateRental() {
// Clear previous error
document.getElementById('errorMsg').style.display = 'none';
document.getElementById('results').style.display = 'none';
// Get Input Values
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPercent = parseFloat(document.getElementById('downPayment').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var years = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var vacancy = parseFloat(document.getElementById('vacancyRate').value);
var mgmt = parseFloat(document.getElementById('mgmtFee').value);
var tax = parseFloat(document.getElementById('propertyTax').value);
var insurance = parseFloat(document.getElementById('insurance').value);
var maint = parseFloat(document.getElementById('maintenance').value);
// Validation
if (isNaN(price) || isNaN(downPercent) || isNaN(rate) || isNaN(years) || isNaN(rent) || isNaN(tax) || isNaN(insurance)) {
document.getElementById('errorMsg').style.display = 'block';
return;
}
// Handle optional % defaults if empty but not NaN (parsefloat returns NaN for empty strings usually, but checking just in case)
if (isNaN(vacancy)) vacancy = 0;
if (isNaN(mgmt)) mgmt = 0;
if (isNaN(maint)) maint = 0;
// Mortgage Calculation
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (rate / 100) / 12;
var totalPayments = years * 12;
var mortgagePayment = 0;
if (rate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, totalPayments)) / (Math.pow(1 + monthlyRate, totalPayments) – 1);
} else {
mortgagePayment = loanAmount / totalPayments;
}
// Expense Calculations (Monthly)
var monthlyTax = tax / 12;
var monthlyIns = insurance / 12;
var vacancyCost = rent * (vacancy / 100);
var mgmtCost = rent * (mgmt / 100);
var maintCost = rent * (maint / 100);
var totalOperatingExpenses = monthlyTax + monthlyIns + vacancyCost + mgmtCost + maintCost;
var totalExpensesWithMortgage = totalOperatingExpenses + mortgagePayment;
// Income Metrics
var noi = rent – totalOperatingExpenses; // Net Operating Income (before debt service)
var cashFlow = noi – mortgagePayment;
var annualCashFlow = cashFlow * 12;
var annualNOI = noi * 12;
// ROI Metrics
// Cash on Cash = Annual Pre-Tax Cash Flow / Total Cash Invested
// Simplifying Total Cash Invested to just Down Payment for this calculator version
var cocReturn = 0;
if (downPaymentAmount > 0) {
cocReturn = (annualCashFlow / downPaymentAmount) * 100;
}
// Cap Rate = Annual NOI / Purchase Price
var capRate = (annualNOI / price) * 100;
// Display Results
var formatter = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
document.getElementById('resMortgage').innerText = formatter.format(mortgagePayment);
document.getElementById('resExpenses').innerText = formatter.format(totalExpensesWithMortgage);
document.getElementById('resNOI').innerText = formatter.format(noi);
document.getElementById('resCashFlow').innerText = formatter.format(cashFlow);
document.getElementById('resCoc').innerText = cocReturn.toFixed(2) + "%";
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
// Styling based on positive/negative cashflow
var cfElement = document.getElementById('resCashFlow');
if (cashFlow >= 0) {
cfElement.style.color = '#27ae60';
} else {
cfElement.style.color = '#c0392b';
}
document.getElementById('results').style.display = 'block';
}
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but simply buying a property doesn't guarantee profit. The most critical metric for any buy-and-hold investor is Cash Flow. This Rental Property Cash Flow Calculator is designed to help investors accurately predict the profitability of a potential investment before signing on the dotted line.
What is Positive Cash Flow?
Positive cash flow occurs when a property's gross monthly income exceeds the total sum of all expenses. This includes the obvious costs like the mortgage payment, but also the often-overlooked "silent killers" of profitability: vacancy rates, maintenance set-asides, property management fees, and capital expenditures (CapEx).
A property with strong positive cash flow acts as an income stream that deposits money into your bank account every month, providing a buffer against market downturns.
Key Metrics Calculated
Net Operating Income (NOI): This is the total income left after operating expenses are paid, but before the mortgage is paid. It is a pure measure of the property's efficiency.
Cash on Cash Return: Perhaps the most important metric for ROI. It measures the annual cash flow relative to the actual cash you invested (Down Payment). A "good" Cash on Cash return typically ranges from 8% to 12% or higher.
Cap Rate (Capitalization Rate): This percentage indicates the rate of return on a real estate investment property based on the income that the property is expected to generate. It is calculated by dividing NOI by the property asset value.
How to Use This Calculator
Purchase Details: Enter the price of the home and your intended down payment percentage.
Loan Specifics: Input current interest rates. Even a 0.5% difference can significantly impact cash flow.
Expenses: Be realistic. Set aside at least 5-10% for vacancies and another 5-10% for maintenance. If you plan to hire a property manager, include their fee (typically 8-12%).
By adjusting these variables, you can determine the maximum offer price that still yields your target return on investment.