function calculateCashFlow() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('rpPurchasePrice').value) || 0;
var closingCosts = parseFloat(document.getElementById('rpClosingCosts').value) || 0;
var downPercent = parseFloat(document.getElementById('rpDownPayment').value) || 0;
var rate = parseFloat(document.getElementById('rpInterestRate').value) || 0;
var termYears = parseFloat(document.getElementById('rpLoanTerm').value) || 0;
var rent = parseFloat(document.getElementById('rpMonthlyRent').value) || 0;
var vacancyPercent = parseFloat(document.getElementById('rpVacancyRate').value) || 0;
var taxYearly = parseFloat(document.getElementById('rpPropertyTax').value) || 0;
var insYearly = parseFloat(document.getElementById('rpInsurance').value) || 0;
var hoa = parseFloat(document.getElementById('rpHOA').value) || 0;
var maintPercent = parseFloat(document.getElementById('rpMaintenance').value) || 0;
var capexPercent = parseFloat(document.getElementById('rpCapex').value) || 0;
var mgmtPercent = parseFloat(document.getElementById('rpManagement').value) || 0;
// 2. Calculations
// Mortgage
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (rate / 100) / 12;
var totalPayments = termYears * 12;
var monthlyMortgage = 0;
if (rate > 0 && termYears > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, totalPayments)) / (Math.pow(1 + monthlyRate, totalPayments) – 1);
} else {
monthlyMortgage = loanAmount / totalPayments;
}
// Operating Expenses
var vacancyCost = rent * (vacancyPercent / 100);
var maintCost = rent * (maintPercent / 100);
var capexCost = rent * (capexPercent / 100);
var mgmtCost = rent * (mgmtPercent / 100);
var taxMonthly = taxYearly / 12;
var insMonthly = insYearly / 12;
var totalOperatingExpenses = vacancyCost + maintCost + capexCost + mgmtCost + taxMonthly + insMonthly + hoa;
var totalMonthlyExpenses = totalOperatingExpenses + monthlyMortgage;
// Key Metrics
var noi = rent – totalOperatingExpenses; // Net Operating Income (monthly)
var cashFlow = rent – totalMonthlyExpenses;
var totalCashInvested = downPaymentAmount + closingCosts;
var annualCashFlow = cashFlow * 12;
var cocReturn = 0;
if (totalCashInvested > 0) {
cocReturn = (annualCashFlow / totalCashInvested) * 100;
}
var annualNOI = noi * 12;
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// 3. Display Results
document.getElementById('rpResults').style.display = 'block';
document.getElementById('resMortgage').innerText = '$' + monthlyMortgage.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resExpenses').innerText = '$' + totalMonthlyExpenses.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resNOI').innerText = '$' + noi.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
var cfElement = document.getElementById('resCashFlow');
cfElement.innerText = '$' + cashFlow.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Change color based on positive/negative cash flow
if (cashFlow >= 0) {
cfElement.className = 'rp-result-value rp-highlight';
} else {
cfElement.className = 'rp-result-value rp-highlight-neg';
}
document.getElementById('resCoC').innerText = cocReturn.toFixed(2) + '%';
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + '%';
}
Understanding Rental Property Cash Flow
Cash flow is the lifeblood of any real estate investment. It represents the net amount of money moving into or out of a business or investment. For rental properties, cash flow is calculated by subtracting all expenses—including mortgage payments, taxes, insurance, and maintenance—from the rental income generated by the property.
Our Rental Property Cash Flow Calculator is designed to help investors accurately predict the profitability of a potential real estate deal. Unlike simple mortgage calculators, this tool accounts for the "hidden" costs of ownership like vacancy rates, capital expenditures (CapEx), and property management fees.
How to Use This Calculator
To get the most accurate results, input values for all fields based on current market data and quotes. Here is a breakdown of the inputs:
Purchase Price & Closing Costs: The total acquisition cost affects your return metrics significantly.
Down Payment & Loan Details: These determine your monthly mortgage payment (Principal & Interest), which is usually the largest expense.
Vacancy Rate: No property is occupied 100% of the time. A standard assumption is 5-8% depending on the local market.
Maintenance & CapEx: Money must be set aside for routine repairs (Maintenance) and big-ticket items like roof or HVAC replacement (CapEx). Allocating 5-10% for each is a prudent conservative strategy.
Key Investment Metrics Defined
This calculator provides three critical metrics to evaluate your deal:
1. Net Operating Income (NOI)
NOI is the total income generated by the property minus all necessary operating expenses. Note: NOI does not include mortgage payments (debt service). It is a pure measure of the property's ability to generate revenue.
2. Cash Flow
This is the actual profit you pocket every month. It is calculated as NOI - Mortgage Payment. Positive cash flow means the property pays for itself and provides income; negative cash flow means you are losing money every month to hold the asset.
3. Cash on Cash Return (CoC)
This metric measures the annual return on the actual cash you invested (Down Payment + Closing Costs). It is calculated as (Annual Cash Flow / Total Cash Invested) x 100. Many investors aim for a CoC return of 8-12% or higher.
4. Cap Rate (Capitalization Rate)
Cap rate indicates the rate of return expected to be generated on a real estate investment property assuming it was bought with cash. It allows you to compare the profitability of different properties regardless of how they are financed.
Why Accurate Expense Estimation Matters
New investors often overestimate cash flow by ignoring vacancy, repairs, and CapEx. By using this comprehensive calculator, you can stress-test your investment against real-world scenarios. Always ensure your numbers work with conservative estimates to protect your financial future.
{
"@context": "https://schema.org",
"@type": "FAQPage",
"mainEntity": [{
"@type": "Question",
"name": "What is a good cash on cash return for rental property?",
"acceptedAnswer": {
"@type": "Answer",
"text": "While targets vary by investor and market, a Cash on Cash (CoC) return of 8% to 12% is generally considered good. In highly appreciative markets, investors might accept lower cash flow (4-6%), while in stable cash-flow markets, investors may seek 12% or higher."
}
}, {
"@type": "Question",
"name": "How do I calculate Net Operating Income (NOI)?",
"acceptedAnswer": {
"@type": "Answer",
"text": "Net Operating Income is calculated by subtracting all operating expenses (Taxes, Insurance, Maintenance, Management, Utilities, Vacancy) from the Total Rental Income. It excludes mortgage payments and income tax."
}
}, {
"@type": "Question",
"name": "What is the 50% rule in real estate?",
"acceptedAnswer": {
"@type": "Answer",
"text": "The 50% rule is a quick heuristic stating that roughly 50% of your rental income will go toward operating expenses (excluding the mortgage). If a property rents for $2,000, you should assume expenses of $1,000. This calculator allows for more precise inputs, but the 50% rule is a good quick check."
}
}]
}