Rental Property Cash Flow Calculator
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Rental Property Calculator
Analyze the cash flow and ROI of your real estate investment.
Investment Analysis
Cash on Cash Return
0.00%
Net Operating Income (Yr)
$0.00
Monthly Mortgage (P&I)
$0.00
Total Monthly Expenses
$0.00
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 a profit. Successful real estate investors rely on accurate math to determine if a specific property is a "deal" or a "dud." This Rental Property Cash Flow Calculator helps you analyze the core metrics used by professionals.
Key Metrics Explained
1. Cash Flow
Cash flow is the profit you bring home each month after all operating expenses and mortgage payments are paid. Positive cash flow means the property pays for itself and provides income. Negative cash flow means you are paying out of pocket to hold the property.
Formula: Gross Rent – (Vacancy + Operating Expenses + Debt Service)
2. Cash on Cash Return (CoC)
This metric measures the annual return on the actual cash you invested (Down Payment + Closing Costs). It is often compared to stock market returns. A CoC of 8-12% is generally considered a solid benchmark for rental properties.
Formula: (Annual Cash Flow / Total Cash Invested) × 100
3. Cap Rate (Capitalization Rate)
Cap rate helps you compare the profitability of a property assuming you bought it with all cash (no loan). It measures the natural rate of return of the property based on its income-generating potential relative to its price.
Formula: (Net Operating Income / Purchase Price) × 100
4. Net Operating Income (NOI)
NOI is the total income the property generates minus all necessary operating expenses (taxes, insurance, maintenance), but excluding the mortgage payment. This number is critical for lenders when valuing commercial or multi-family properties.
What are Common Expense Estimates?
- Vacancy Rate: Typically 5-8% depending on the local market demand.
- Maintenance: Investors often budget 1% of the property value per year, or 10% of the monthly rent.
- Property Management: If you hire a manager, expect to pay 8-10% of the monthly rent.
The 1% Rule
A quick rule of thumb used by investors to filter properties is the 1% Rule. It states that the monthly rent should be at least 1% of the purchase price. For example, a $200,000 home should rent for at least $2,000/month. While not a hard rule, properties meeting this criteria are more likely to generate positive cash flow.
function calculateRental() {
// 1. Get Inputs using var
var price = parseFloat(document.getElementById('propPrice').value) || 0;
var downPmt = parseFloat(document.getElementById('downPayment').value) || 0;
var rate = parseFloat(document.getElementById('intRate').value) || 0;
var years = parseFloat(document.getElementById('loanTerm').value) || 0;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var vacancyPct = parseFloat(document.getElementById('vacancyRate').value) || 0;
var taxYear = parseFloat(document.getElementById('propTax').value) || 0;
var insYear = parseFloat(document.getElementById('homeIns').value) || 0;
var repairMo = parseFloat(document.getElementById('repairs').value) || 0;
var hoaMo = parseFloat(document.getElementById('hoa').value) || 0;
// 2. Calculate Mortgage (Principal & Interest)
var loanAmount = price – downPmt;
var monthlyRate = (rate / 100) / 12;
var numPayments = years * 12;
var monthlyMortgage = 0;
if (rate > 0 && years > 0 && loanAmount > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
}
// 3. Calculate Income Logic
var vacancyLossMo = rent * (vacancyPct / 100);
var effectiveRentMo = rent – vacancyLossMo;
// 4. Calculate Expenses Logic
var taxMo = taxYear / 12;
var insMo = insYear / 12;
var operatingExpMo = taxMo + insMo + repairMo + hoaMo;
var totalExpMo = operatingExpMo + monthlyMortgage;
// 5. Calculate Metrics
var monthlyCashFlow = effectiveRentMo – totalExpMo;
var annualCashFlow = monthlyCashFlow * 12;
var annualNOI = (effectiveRentMo * 12) – (operatingExpMo * 12);
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
var cocReturn = 0;
if (downPmt > 0) {
cocReturn = (annualCashFlow / downPmt) * 100;
}
// 6. Formatting Helper
function formatCurrency(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
function formatPercent(num) {
return num.toFixed(2) + "%";
}
// 7. Update DOM
document.getElementById('resMortgage').innerText = formatCurrency(monthlyMortgage);
document.getElementById('resExpenses').innerText = formatCurrency(totalExpMo);
document.getElementById('resNOI').innerText = formatCurrency(annualNOI);
document.getElementById('resCapRate').innerText = formatPercent(capRate);
document.getElementById('resCoC').innerText = formatPercent(cocReturn);
var cfElement = document.getElementById('resCashFlow');
cfElement.innerText = formatCurrency(monthlyCashFlow);
// Style Cash Flow positive/negative
if (monthlyCashFlow >= 0) {
cfElement.className = "result-value positive";
} else {
cfElement.className = "result-value negative";
}
// Show results
document.getElementById('resultsArea').style.display = "block";
}