Please enter valid positive numbers for all fields.
Analysis Results
Monthly Rental Income (Adjusted for Vacancy):$0.00
Monthly Mortgage (P&I):$0.00
Total Monthly Expenses (incl. Mortgage):$0.00
Net Monthly Cash Flow:$0.00
Cash on Cash Return (ROI):0.00%
Cap Rate:0.00%
Total Cash Required to Close:$0.00
function calculateCashFlow() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('purchasePrice').value);
var downPercent = parseFloat(document.getElementById('downPayment').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var years = parseFloat(document.getElementById('loanTerm').value);
var rent = parseFloat(document.getElementById('monthlyRent').value);
var vacancy = parseFloat(document.getElementById('vacancyRate').value);
var tax = parseFloat(document.getElementById('propertyTax').value);
var insurance = parseFloat(document.getElementById('insurance').value);
var maintPercent = parseFloat(document.getElementById('maintenance').value);
var hoa = parseFloat(document.getElementById('hoaFees').value);
// 2. Validation
if (isNaN(price) || isNaN(downPercent) || isNaN(rate) || isNaN(years) ||
isNaN(rent) || isNaN(vacancy) || isNaN(tax) || isNaN(insurance) ||
isNaN(maintPercent) || isNaN(hoa)) {
document.getElementById('errorMsg').style.display = 'block';
document.getElementById('results').style.display = 'none';
return;
}
document.getElementById('errorMsg').style.display = 'none';
// 3. Loan Calculations
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var monthlyRate = (rate / 100) / 12;
var totalPayments = years * 12;
var mortgagePayment = 0;
if (rate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, totalPayments)) / (Math.pow(1 + monthlyRate, totalPayments) – 1);
} else {
mortgagePayment = loanAmount / totalPayments;
}
// 4. Operating Calculations
var monthlyVacancyCost = rent * (vacancy / 100);
var effectiveRent = rent – monthlyVacancyCost;
var monthlyTax = tax / 12;
var monthlyIns = insurance / 12;
var monthlyMaint = (price * (maintPercent / 100)) / 12;
var operatingExpenses = monthlyTax + monthlyIns + monthlyMaint + hoa; // Excludes mortgage
var totalMonthlyExpenses = operatingExpenses + mortgagePayment;
var cashFlow = effectiveRent – totalMonthlyExpenses;
var annualCashFlow = cashFlow * 12;
// 5. ROI Metrics
// Net Operating Income (Annual) = (Effective Rent * 12) – (Operating Expenses * 12)
var annualNOI = (effectiveRent * 12) – (operatingExpenses * 12);
// Cap Rate = (NOI / Purchase Price) * 100
var capRate = (annualNOI / price) * 100;
// Cash to Close (Down Payment + assumed 2% closing costs for estimation)
var closingCosts = price * 0.02;
var totalCashInvested = downPaymentAmount + closingCosts;
// Cash on Cash Return = (Annual Pre-Tax Cash Flow / Total Cash Invested) * 100
var cashOnCash = (annualCashFlow / totalCashInvested) * 100;
// 6. Display Results
document.getElementById('resIncome').innerText = "$" + effectiveRent.toFixed(2);
document.getElementById('resMortgage').innerText = "$" + mortgagePayment.toFixed(2);
document.getElementById('resExpenses').innerText = "$" + totalMonthlyExpenses.toFixed(2);
document.getElementById('resCashFlow').innerText = "$" + cashFlow.toFixed(2);
// Color coding cash flow
var cashFlowElem = document.getElementById('resCashFlow');
if (cashFlow >= 0) {
cashFlowElem.style.color = "#27ae60";
} else {
cashFlowElem.style.color = "#c0392b";
}
document.getElementById('resCoc').innerText = cashOnCash.toFixed(2) + "%";
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resCashToClose').innerText = "$" + totalCashInvested.toFixed(2) + " (est)";
document.getElementById('results').style.display = 'block';
}
How to Analyze Rental Properties for Maximum Profit
Investing in real estate is one of the most reliable ways to build long-term wealth, but not every property is a good deal. Using a Rental Property Cash Flow Calculator is essential to distinguish between an asset that puts money in your pocket and a liability that drains your bank account. This tool helps investors analyze the financial viability of a potential rental property by calculating key metrics like Cash Flow, Cap Rate, and Cash on Cash Return.
Understanding Net Monthly Cash Flow
Cash flow is the lifeblood of any rental investment. It represents the money left over after all expenses are paid. The formula used in this calculator is:
Gross Income: Total rent collected.
Vacancy Loss: Estimated income lost due to empty units (typically 5-10%).
Operating Expenses: Taxes, insurance, HOA fees, and maintenance reserves.
Debt Service: Your monthly mortgage principal and interest payments.
A positive cash flow ensures the property pays for itself and provides you with passive income. Most investors aim for at least $100-$200 per door in net positive cash flow.
Cash on Cash Return vs. Cap Rate
Two critical metrics in real estate analysis are the Cap Rate and Cash on Cash Return (CoC). While they may seem similar, they serve different purposes:
Capitalization Rate (Cap Rate): This measures the natural rate of return of the property assuming you paid all cash. It is calculated by dividing the Net Operating Income (NOI) by the Purchase Price. It allows you to compare the profitability of different properties regardless of how they are financed.
Cash on Cash Return: This metric is vital for investors using leverage (mortgages). It calculates the annual cash return relative to the actual cash you invested (down payment + closing costs). A higher CoC means your specific capital is working harder for you. In many markets, a CoC return of 8-12% is considered a strong investment target.
Estimating Expenses Correctly
The number one mistake new investors make is underestimating expenses. Always account for:
Maintenance Reserves: Even if the house is new, things break. Set aside 1% of the property value annually.
Vacancy: You won't have a tenant 100% of the time. Budget for at least 5% vacancy.
Property Management: Even if you self-manage now, value your time. Management typically costs 10% of gross rent.
By using this calculator and inputting conservative expense estimates, you can make data-driven decisions and build a profitable real estate portfolio.