Analyze your potential real estate investment deals accurately.
Purchase Information
Financing Details
30 Years
15 Years
10 Years
Rental Income
Recurring Expenses
Analysis Results
Monthly Cash Flow—
Cash on Cash Return (ROI)—
Cap Rate—
Income Breakdown
Gross Rent:
Vacancy Loss: Effective Gross Income:
Expense Breakdown (Monthly)
Mortgage (P&I):
Taxes/Ins/HOA:
Variable (Maint/CapEx/Mgmt): Total Expenses:
Understanding Rental Property Cash Flow
Investing in real estate is one of the most reliable ways to build wealth, but the difference between a good investment and a money pit lies in the numbers. This Rental Property Cash Flow Calculator helps investors analyze the potential profitability of a residential rental property.
What is Cash Flow?
Cash flow is the net amount of cash moving into and out of a business. In real estate, it represents the money left over after all operating expenses and mortgage payments have been collected from the rental income. Positive cash flow means the property generates income, while negative cash flow implies the investor must contribute money monthly to keep the property afloat.
Key Metrics Explained
NOI (Net Operating Income): This is your annual income minus all operating expenses, but excluding the mortgage payment. It measures the raw profitability of the asset itself.
Cash on Cash Return (CoC): A percentage measuring the annual pre-tax cash flow divided by the total cash invested (down payment + closing costs). It tells you how hard your actual dollars are working.
Cap Rate (Capitalization Rate): Calculated as NOI divided by the property's purchase price. It allows you to compare the profitability of different properties regardless of how they are financed.
CapEx (Capital Expenditures): Funds set aside for major future replacements, such as a new roof, HVAC system, or water heater. Ignoring CapEx is a common mistake for new investors.
How to Use This Calculator
Purchase Info: Enter the price of the home and your estimated closing costs.
Financing: Input your down payment percentage, interest rate, and loan term. This determines your monthly mortgage payment (Principal & Interest).
Income: Enter the expected monthly rent. Be realistic—check local listings for comparable properties ("comps").
Expenses: Fill out taxes, insurance, and HOA fees accurately. Do not skip the percentage-based expenses like Vacancy (usually 5-8%), Maintenance (5-10%), and CapEx (5-10%). Even if the house is new, things break and tenants move out.
Interpreting Your Results
Ideally, you want a positive monthly cash flow. Many investors aim for $100-$200 per door in pure cash flow after all expenses. A Cash on Cash return of 8-12% is generally considered good in many markets, though this varies significantly by location and strategy.
Why Include Vacancy and Maintenance?
One of the biggest errors beginners make is assuming a property will be rented 100% of the time with zero repairs. By factoring in a vacancy rate (money lost while finding a tenant) and maintenance reserves, you protect your investment against inevitable real-world costs.
function calculateCashFlow() {
// 1. Get Inputs using var
var price = parseFloat(document.getElementById('prop_price').value) || 0;
var closing = parseFloat(document.getElementById('closing_costs').value) || 0;
var downPercent = parseFloat(document.getElementById('down_payment_percent').value) || 0;
var interestRate = parseFloat(document.getElementById('interest_rate').value) || 0;
var termYears = parseFloat(document.getElementById('loan_term').value) || 30;
var grossRent = parseFloat(document.getElementById('monthly_rent').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancy_rate').value) || 0;
var taxAnnual = parseFloat(document.getElementById('property_tax').value) || 0;
var insuranceAnnual = parseFloat(document.getElementById('insurance').value) || 0;
var hoaMonthly = parseFloat(document.getElementById('hoa_fee').value) || 0;
var maintRate = parseFloat(document.getElementById('repairs_maintenance').value) || 0;
var capexRate = parseFloat(document.getElementById('capex').value) || 0;
var mgmtRate = parseFloat(document.getElementById('management_fee').value) || 0;
// 2. Calculate Initial Investment & Loan
var downPayment = price * (downPercent / 100);
var loanAmount = price – downPayment;
var totalCashInvested = downPayment + closing;
// 3. Calculate Mortgage (Principal + Interest)
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
var monthlyRate = (interestRate / 100) / 12;
var numPayments = termYears * 12;
var mortgagePayment = 0;
if (loanAmount > 0 && interestRate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numPayments)) / (Math.pow(1 + monthlyRate, numPayments) – 1);
} else if (loanAmount > 0 && interestRate === 0) {
mortgagePayment = loanAmount / numPayments;
}
// 4. Calculate Monthly Expenses
var vacancyCost = grossRent * (vacancyRate / 100);
var effectiveIncome = grossRent – vacancyCost;
var taxMonthly = taxAnnual / 12;
var insuranceMonthly = insuranceAnnual / 12;
var maintCost = grossRent * (maintRate / 100);
var capexCost = grossRent * (capexRate / 100);
var mgmtCost = grossRent * (mgmtRate / 100);
var totalFixedExpenses = taxMonthly + insuranceMonthly + hoaMonthly;
var totalVariableExpenses = maintCost + capexCost + mgmtCost;
var totalOperatingExpenses = totalFixedExpenses + totalVariableExpenses; // Without Mortgage
var totalMonthlyExpenses = totalOperatingExpenses + mortgagePayment;
// 5. Calculate Metrics
var monthlyCashFlow = effectiveIncome – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// NOI = Income – Operating Expenses (No Mortgage)
var monthlyNOI = effectiveIncome – totalOperatingExpenses;
var annualNOI = monthlyNOI * 12;
var capRate = (price > 0) ? (annualNOI / price) * 100 : 0;
var cocReturn = (totalCashInvested > 0) ? (annualCashFlow / totalCashInvested) * 100 : 0;
// 6. Display Results
var resultDiv = document.getElementById('results');
resultDiv.style.display = "block";
// Helper for formatting currency
function formatMoney(num) {
return "$" + num.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
}
function formatPercent(num) {
return num.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2}) + "%";
}
var cashFlowEl = document.getElementById('res_cash_flow');
cashFlowEl.innerText = formatMoney(monthlyCashFlow);
cashFlowEl.className = "result-value " + (monthlyCashFlow >= 0 ? "positive" : "negative");
var cocEl = document.getElementById('res_coc');
cocEl.innerText = formatPercent(cocReturn);
cocEl.className = "result-value " + (cocReturn >= 0 ? "positive" : "negative");
document.getElementById('res_cap_rate').innerText = formatPercent(capRate);
// Breakdown display
document.getElementById('res_gross_rent').innerText = formatMoney(grossRent);
document.getElementById('res_vacancy').innerText = "-" + formatMoney(vacancyCost);
document.getElementById('res_egi').innerText = formatMoney(effectiveIncome);
document.getElementById('res_mortgage').innerText = formatMoney(mortgagePayment);
document.getElementById('res_fixed_exp').innerText = formatMoney(totalFixedExpenses);
document.getElementById('res_var_exp').innerText = formatMoney(totalVariableExpenses);
document.getElementById('res_total_exp').innerText = formatMoney(totalMonthlyExpenses);
}