Rental Property Cash Flow Calculator
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Monthly Financial Analysis
Effective Gross Income:
$0.00
Total Operating Expenses:
$0.00
Net Operating Income (NOI):
$0.00
Total Mortgage Payment:
$0.00
Monthly Cash Flow:
$0.00
Annual Cash Flow:
$0.00
Understanding Rental Property Cash Flow
Cash flow is the lifeblood of any real estate investment. It represents the profit you bring in each month after all expenses, including your mortgage, taxes, insurance, and maintenance reserves, have been paid. A positive cash flow indicates a healthy investment that generates passive income, while negative cash flow means the property is costing you money to hold.
How to Use This Calculator
This calculator helps investors estimate the potential returns on a rental property by accounting for both fixed costs and variable estimates. Here is a breakdown of the inputs required:
- Gross Monthly Rent: The total rent you expect to collect from tenants.
- Vacancy Rate: A percentage estimation of how often the property will sit empty. A standard conservative estimate is 5-8%.
- Repairs & CapEx: Money set aside for routine repairs (leaky faucets) and large capital expenditures (new roof, HVAC). Setting aside 5-10% for each is a prudent strategy.
- Property Management: If you hire a professional manager, they typically charge 8-12% of the collected rent. Even if you self-manage, it is wise to factor this in as an "opportunity cost."
Key Metrics Explained
Net Operating Income (NOI): This is your total income minus all operating expenses, excluding the mortgage payment. It measures the profitability of the property itself, regardless of financing.
Cash Flow: This is your NOI minus the mortgage (debt service). This is the actual cash that ends up in your pocket (or bank account) every month.
The 50% Rule and 1% Rule
Real estate investors often use "rules of thumb" for quick screening. The 50% Rule suggests that operating expenses (excluding mortgage) will average out to 50% of the gross rent over time. The 1% Rule suggests that for a property to be cash flow positive, the monthly rent should be at least 1% of the purchase price. While these rules are helpful for screening, this calculator provides a much more detailed analysis based on specific numbers.
function calculateRentalCashFlow() {
// 1. Get Inputs
var monthlyRent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var otherIncome = parseFloat(document.getElementById('otherIncome').value) || 0;
var mortgagePayment = parseFloat(document.getElementById('mortgagePayment').value) || 0;
var propertyTax = parseFloat(document.getElementById('propertyTax').value) || 0;
var insurance = parseFloat(document.getElementById('insurance').value) || 0;
var hoaFees = parseFloat(document.getElementById('hoaFees').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var repairsRate = parseFloat(document.getElementById('repairsMaint').value) || 0;
var capexRate = parseFloat(document.getElementById('capex').value) || 0;
var managementRate = parseFloat(document.getElementById('managementFee').value) || 0;
// 2. Calculate Income
var grossPotentialIncome = monthlyRent + otherIncome;
var vacancyLoss = grossPotentialIncome * (vacancyRate / 100);
var effectiveGrossIncome = grossPotentialIncome – vacancyLoss;
// 3. Calculate Variable Expenses (Based on Gross Income generally, but usually management is on collected)
// For simplicity in this tool, we apply percentages to Gross Potential Income for maintenance/capex
// and Effective Gross Income for Management (managers usually paid on collected rent).
var repairsCost = grossPotentialIncome * (repairsRate / 100);
var capexCost = grossPotentialIncome * (capexRate / 100);
var managementCost = effectiveGrossIncome * (managementRate / 100);
// 4. Calculate Total Expenses (Operating)
var totalOperatingExpenses = propertyTax + insurance + hoaFees + repairsCost + capexCost + managementCost;
// 5. Calculate Metrics
var noi = effectiveGrossIncome – totalOperatingExpenses;
var monthlyCashFlow = noi – mortgagePayment;
var annualCashFlow = monthlyCashFlow * 12;
// 6. Formatting Function
function formatCurrency(num) {
return '$' + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
// 7. Update DOM
document.getElementById('res-gross-income').innerText = formatCurrency(effectiveGrossIncome);
document.getElementById('res-operating-expenses').innerText = formatCurrency(totalOperatingExpenses);
document.getElementById('res-noi').innerText = formatCurrency(noi);
document.getElementById('res-mortgage').innerText = formatCurrency(mortgagePayment);
var monthlyEl = document.getElementById('res-monthly-cf');
var annualEl = document.getElementById('res-annual-cf');
monthlyEl.innerText = formatCurrency(monthlyCashFlow);
annualEl.innerText = formatCurrency(annualCashFlow);
// Styling for negative/positive
if (monthlyCashFlow < 0) {
monthlyEl.classList.add('negative-flow');
annualEl.classList.add('negative-flow');
} else {
monthlyEl.classList.remove('negative-flow');
annualEl.classList.remove('negative-flow');
}
// Show results
document.getElementById('results').style.display = 'block';
}