Analyze your real estate investment performance instantly.
Purchase Information
Inspections, origination fees, etc.
Loan Details
Income & Expenses
% of rent set aside for repairs
Investment Analysis
Monthly Cash Flow$0.00
Cash on Cash Return (ROI)0.00%
Cap Rate0.00%
Total Monthly Expenses$0.00
function calculateCashFlow() {
// Get Inputs
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var down = parseFloat(document.getElementById('downPayment').value) || 0;
var closing = parseFloat(document.getElementById('closingCosts').value) || 0;
var rate = parseFloat(document.getElementById('interestRate').value) || 0;
var years = parseFloat(document.getElementById('loanTerm').value) || 0;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var taxAnnual = parseFloat(document.getElementById('propertyTax').value) || 0;
var insAnnual = parseFloat(document.getElementById('insurance').value) || 0;
var hoa = parseFloat(document.getElementById('hoa').value) || 0;
var vacancyPct = parseFloat(document.getElementById('vacancyRate').value) || 0;
var maintPct = parseFloat(document.getElementById('maintenanceRate').value) || 0;
// Calculate Loan Payment (Principal & Interest)
var loanAmount = price – down;
var monthlyRate = (rate / 100) / 12;
var numberOfPayments = years * 12;
var mortgagePayment = 0;
if (loanAmount > 0 && rate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else if (loanAmount > 0 && rate === 0) {
mortgagePayment = loanAmount / numberOfPayments;
}
// Calculate Operating Expenses
var monthlyTax = taxAnnual / 12;
var monthlyIns = insAnnual / 12;
var monthlyVacancy = rent * (vacancyPct / 100);
var monthlyMaint = rent * (maintPct / 100);
var totalMonthlyExpenses = mortgagePayment + monthlyTax + monthlyIns + hoa + monthlyVacancy + monthlyMaint;
// Calculate Cash Flow
var cashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = cashFlow * 12;
// Calculate Cash on Cash Return
// CoC = Annual Cash Flow / Total Cash Invested (Down Payment + Closing Costs)
var totalInvested = down + closing;
var cocReturn = 0;
if (totalInvested > 0) {
cocReturn = (annualCashFlow / totalInvested) * 100;
}
// Calculate Cap Rate
// Cap Rate = Net Operating Income (NOI) / Purchase Price
// NOI = Annual Rent – Annual Operating Expenses (excluding Mortgage)
var annualOperatingExpenses = (monthlyTax + monthlyIns + hoa + monthlyVacancy + monthlyMaint) * 12;
var annualNOI = (rent * 12) – annualOperatingExpenses;
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
// Update UI
var cashFlowEl = document.getElementById('monthlyCashFlow');
cashFlowEl.innerText = '$' + cashFlow.toFixed(2);
if(cashFlow >= 0) {
cashFlowEl.className = 'result-value positive';
} else {
cashFlowEl.className = 'result-value negative';
}
document.getElementById('cashOnCash').innerText = cocReturn.toFixed(2) + '%';
document.getElementById('capRate').innerText = capRate.toFixed(2) + '%';
document.getElementById('totalExpenses').innerText = '$' + totalMonthlyExpenses.toFixed(2);
// Show results
document.getElementById('results').style.display = 'block';
}
Understanding Rental Property Cash Flow
Successful real estate investing relies on math, not emotion. This Rental Property Cash Flow Calculator helps investors determine if a property will generate a profit (positive cash flow) or cost money to hold (negative cash flow). By analyzing key metrics like Cash on Cash Return and Cap Rate, you can make data-driven decisions before making an offer.
Key Metrics Explained
1. Monthly Cash Flow
Cash flow is the net amount of money left over after all expenses are paid. It is calculated as:
Gross Income: Your monthly rent.
Minus Expenses: Mortgage (P&I), property taxes, insurance, HOA fees, vacancy reserves, and maintenance costs.
A positive cash flow ensures the property pays for itself and provides passive income. Most investors aim for at least $200–$300 per door in positive cash flow.
2. Cash on Cash Return (CoC ROI)
This is arguably the most important metric for rental investors. It measures the return on the actual cash you invested, not the total loan amount. It answers the question: "For every dollar I put into this deal, how much am I getting back annually?"
A CoC return of 8-12% is generally considered good, while anything above 15% is excellent in most markets.
3. Cap Rate (Capitalization Rate)
Cap Rate measures the natural profitability of a property assuming you bought it with all cash (no mortgage). It allows you to compare the potential of different properties regardless of how they are financed.
Formula: Net Operating Income (NOI) / Purchase Price
Common Expenses Investors Forget
When using this calculator, ensure you account for "hidden" costs to get an accurate result:
Vacancy Rate: Properties won't be rented 365 days a year. Use 5-8% to account for turnover periods.
Maintenance & CapEx: Roofs leak and toilets break. Setting aside 5-10% of monthly rent ensures you have funds ready when repairs are needed.
Property Management: Even if you self-manage now, factoring in 8-10% for management ensures the deal still works if you hire a professional later.
How to Improve Your Cash Flow
If the calculator shows a negative or low return, consider these strategies:
Negotiate the Price: Lowering the purchase price reduces your loan amount and monthly mortgage payment.
Increase Down Payment: Putting more money down reduces the loan size, lowering monthly debt service.
Value-Add: Can you renovate to increase the rent? Higher income improves both Cash Flow and Cap Rate.
Shop for Insurance: Lowering annual premiums directly boosts your bottom line.