Analyze your real estate investment deal in seconds.
Purchase & Loan Details
Monthly Income
Monthly Expenses & Reserves
0.00%
Cash on Cash Return
0.00%
Cap Rate
$0
Monthly Cash Flow
Monthly Income:$0
Monthly Mortgage (P&I):$0
Monthly Operating Expenses:$0
Net Operating Income (Monthly):$0
Total Monthly Cash Flow:$0
function calculateRental() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('rpc-price').value) || 0;
var downPercent = parseFloat(document.getElementById('rpc-down').value) || 0;
var rate = parseFloat(document.getElementById('rpc-rate').value) || 0;
var termYears = parseFloat(document.getElementById('rpc-term').value) || 0;
var closingCosts = parseFloat(document.getElementById('rpc-closing').value) || 0;
var rent = parseFloat(document.getElementById('rpc-rent').value) || 0;
var otherIncome = parseFloat(document.getElementById('rpc-other-income').value) || 0;
var annualTax = parseFloat(document.getElementById('rpc-tax').value) || 0;
var annualIns = parseFloat(document.getElementById('rpc-insurance').value) || 0;
var monthlyHoa = parseFloat(document.getElementById('rpc-hoa').value) || 0;
var vacancyRate = parseFloat(document.getElementById('rpc-vacancy').value) || 0;
var maintRate = parseFloat(document.getElementById('rpc-maint').value) || 0;
var pmRate = parseFloat(document.getElementById('rpc-pm').value) || 0;
// 2. Calculations
// Investment Capital
var downPayment = price * (downPercent / 100);
var loanAmount = price – downPayment;
var totalCashInvested = downPayment + closingCosts;
// Mortgage Payment (P&I)
var monthlyRate = (rate / 100) / 12;
var numberOfPayments = termYears * 12;
var mortgagePayment = 0;
if (rate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
mortgagePayment = loanAmount / numberOfPayments;
}
// Monthly Income
var totalMonthlyIncome = rent + otherIncome;
// Variable Monthly Expenses
var vacancyCost = totalMonthlyIncome * (vacancyRate / 100);
var maintCost = totalMonthlyIncome * (maintRate / 100);
var pmCost = totalMonthlyIncome * (pmRate / 100);
// Fixed Monthly Expenses
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
// Total Operating Expenses (excluding mortgage)
var operatingExpenses = monthlyTax + monthlyIns + monthlyHoa + vacancyCost + maintCost + pmCost;
// Net Operating Income (NOI)
var monthlyNOI = totalMonthlyIncome – operatingExpenses;
var annualNOI = monthlyNOI * 12;
// Cash Flow
var monthlyCashFlow = monthlyNOI – mortgagePayment;
var annualCashFlow = monthlyCashFlow * 12;
// Returns
var capRate = (price > 0) ? (annualNOI / price) * 100 : 0;
var cashOnCash = (totalCashInvested > 0) ? (annualCashFlow / totalCashInvested) * 100 : 0;
// 3. Display Results
// Helper for currency formatting
var fmt = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
document.getElementById('rpc-disp-income').innerText = fmt.format(totalMonthlyIncome);
document.getElementById('rpc-disp-mortgage').innerText = fmt.format(mortgagePayment);
document.getElementById('rpc-disp-opex').innerText = fmt.format(operatingExpenses);
document.getElementById('rpc-disp-noi').innerText = fmt.format(monthlyNOI);
var finalEl = document.getElementById('rpc-disp-final');
finalEl.innerText = fmt.format(monthlyCashFlow);
if(monthlyCashFlow >= 0) {
finalEl.className = "rpc-positive";
} else {
finalEl.className = "rpc-negative";
}
document.getElementById('rpc-coc').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('rpc-cap').innerText = capRate.toFixed(2) + "%";
var cfMetric = document.getElementById('rpc-monthly-cf');
cfMetric.innerText = fmt.format(monthlyCashFlow);
cfMetric.style.color = monthlyCashFlow >= 0 ? "#27ae60" : "#c0392b";
// Show results
document.getElementById('rpc-results').style.display = 'block';
}
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but the difference between a successful investment and a financial burden often comes down to one metric: Cash Flow. This calculator is designed to help investors objectively analyze rental properties by accounting for all income and potential expenses.
What is Positive Cash Flow?
Positive cash flow occurs when a property's gross monthly income exceeds the total sum of all expenses, including the mortgage, taxes, insurance, and maintenance reserves. In essence, it is the profit you pocket every month just for owning the property. Properties with strong positive cash flow provide a safety net against vacancies and unexpected repairs while generating passive income.
Key Metrics Used in This Calculator
To accurately evaluate a deal, you need to understand the following return on investment (ROI) metrics:
NOI (Net Operating Income): This is your total income minus operating expenses. Crucially, NOI excludes mortgage payments. It represents the profitability of the property itself, regardless of how it is financed.
Cap Rate (Capitalization Rate): Calculated as Annual NOI / Purchase Price. The Cap Rate allows you to compare the profitability of different properties as if you paid all cash. A higher Cap Rate generally indicates a better return, though often comes with higher risk.
Cash on Cash Return: Calculated as Annual Cash Flow / Total Cash Invested. This is arguably the most important metric for leveraged investors. It tells you exactly how hard your actual dollars (down payment + closing costs) are working for you.
The 50% Rule and 1% Rule
While this calculator provides precise numbers, investors often use "napkin math" rules for quick screening:
The 1% Rule: Suggests that the monthly rent should be at least 1% of the purchase price. For a $200,000 home, rent should be $2,000+.
The 50% Rule: Estimates that 50% of your gross rent will go toward operating expenses (taxes, insurance, maintenance, vacancy), not including the mortgage. If your mortgage payment is greater than the remaining 50%, the property will likely have negative cash flow.
Hidden Expenses to Watch For
New investors often overestimate cash flow by ignoring "phantom" expenses. This calculator includes fields for:
Vacancy Rate: Properties won't be occupied 365 days a year. Budgeting 5-8% allows you to cover costs during turnover periods.
CapEx (Capital Expenditures): Separate from routine maintenance, CapEx covers big-ticket items like a new roof or HVAC system. Setting aside 5-10% of rent monthly ensures you aren't bankrupted when these systems fail.
Property Management: Even if you self-manage now, budgeting 8-10% for management ensures the deal still works if you decide to hire a professional later.
How to Use These Results
If the calculator shows a negative cash flow, you have three options: negotiate a lower purchase price, increase the down payment to lower the mortgage, or walk away. A good investment should generally provide a Cash on Cash return that beats the stock market or inflation, typically aiming for 8-12% or higher depending on your market strategy.