Total Fixed Expenses (Mortgage, Tax, HOA, Ins):$0.00
Total Monthly Outflow:$0.00
Net Monthly Cash Flow
$0.00
Why Use a Rental Property Cash Flow Calculator?
Successful real estate investing isn't about guessing; it's about mathematics. The Rental Property Cash Flow Calculator is designed to help investors determine the true profitability of a potential investment property. By subtracting all operating expenses, mortgage payments, and necessary reserves from your rental income, you get a clear picture of your net profit—or cash flow.
How to Calculate Rental Cash Flow
The basic formula for cash flow is simple: Income – Expenses = Cash Flow. However, many new investors make the mistake of underestimating expenses. This calculator accounts for the "hidden" costs that eat into profits:
Vacancy Rate: Properties don't stay rented 100% of the time. We recommend estimating a 5-8% vacancy allowance.
Maintenance & CapEx: Roofs leak and appliances break. Setting aside 10-15% of rent ensures you have funds when repairs are needed.
Fixed Costs: Taxes, insurance, and HOA fees are recurring monthly obligations that must be paid regardless of occupancy.
What is a Good Cash Flow?
While "good" is subjective based on your investment strategy, many investors look for the "1% Rule" (monthly rent is 1% of purchase price) or aim for $100-$300 in positive cash flow per door per month. Positive cash flow ensures the property pays for itself and provides passive income, while negative cash flow means you are paying out of pocket to hold the asset.
Interpreting Your Results
If your result is green, the property generates income. If the result is red, the property has a negative cash flow. Be cautious with negative cash flow properties unless you are banking on significant appreciation or have a specific tax strategy in mind.
function calculateRentalCashFlow() {
// 1. Get Input Values
// Using parseFloat and checking for NaN to ensure math validity
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var otherIncome = parseFloat(document.getElementById('otherIncome').value) || 0;
var mortgage = parseFloat(document.getElementById('mortgagePayment').value) || 0;
var tax = parseFloat(document.getElementById('propertyTax').value) || 0;
var insurance = parseFloat(document.getElementById('insurance').value) || 0;
var hoa = parseFloat(document.getElementById('hoaFees').value) || 0;
var vacancyPercent = parseFloat(document.getElementById('vacancyRate').value) || 0;
var maintenancePercent = parseFloat(document.getElementById('maintenanceRate').value) || 0;
// 2. Perform Calculations
// Total Potential Income
var grossIncome = rent + otherIncome;
// Calculate Reserves (Variable Expenses)
// These are calculated based on the total potential income
var vacancyCost = grossIncome * (vacancyPercent / 100);
var maintenanceCost = grossIncome * (maintenancePercent / 100);
var totalVariableCosts = vacancyCost + maintenanceCost;
// Calculate Fixed Expenses
var totalFixedExpenses = mortgage + tax + insurance + hoa;
// Total Expenses (Fixed + Variable)
var totalExpenses = totalFixedExpenses + totalVariableCosts;
// Net Cash Flow
var cashFlow = grossIncome – totalExpenses;
// 3. Update UI / Display Results
// Helper function for currency formatting
function formatMoney(amount) {
return "$" + amount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
// Display breakdown
document.getElementById('displayGrossIncome').innerHTML = formatMoney(grossIncome);
document.getElementById('displayLosses').innerHTML = "-" + formatMoney(totalVariableCosts);
document.getElementById('displayFixedExpenses').innerHTML = "-" + formatMoney(totalFixedExpenses);
document.getElementById('displayTotalExpenses').innerHTML = "-" + formatMoney(totalExpenses);
// Display Main Result with Styling for Positive/Negative
var resultElement = document.getElementById('displayCashFlow');
var resultBox = document.getElementById('mainResultBox');
var resultLabel = document.getElementById('cashFlowLabel');
resultElement.innerHTML = formatMoney(cashFlow);
if (cashFlow < 0) {
// Negative Cash Flow Styles
resultElement.classList.add('rp-negative-text');
resultBox.classList.add('rp-negative-bg');
resultLabel.classList.add('rp-negative-text');
resultLabel.innerHTML = "NEGATIVE CASH FLOW";
} else {
// Positive Cash Flow Styles (Reset)
resultElement.classList.remove('rp-negative-text');
resultBox.classList.remove('rp-negative-bg');
resultLabel.classList.remove('rp-negative-text');
resultLabel.innerHTML = "POSITIVE CASH FLOW";
}
// Show the results section
document.getElementById('rpResults').style.display = "block";
}