Analyze your real estate investment deal instantly.
Purchase Information
Loan Details
30 Years
15 Years
10 Years
Income & Expenses
Monthly Financial Summary
Gross Rental Income:$0.00
Principal & Interest (Mortgage):$0.00
Total Monthly Expenses (Operating):$0.00
Net Monthly Cash Flow:$0.00
Annual Investment Returns
Net Operating Income (NOI):$0.00
Cap Rate:0.00%
Total Cash Invested (Down + Closing):$0.00
Cash on Cash Return:0.00%
function calculateRental() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('rpc_price').value);
var closingCosts = parseFloat(document.getElementById('rpc_closing').value);
var downPercent = parseFloat(document.getElementById('rpc_down_percent').value);
var interestRate = parseFloat(document.getElementById('rpc_interest').value);
var termYears = parseFloat(document.getElementById('rpc_term').value);
var rentIncome = parseFloat(document.getElementById('rpc_rent').value);
var annualTax = parseFloat(document.getElementById('rpc_tax').value);
var annualIns = parseFloat(document.getElementById('rpc_insurance').value);
var monthlyHOA = parseFloat(document.getElementById('rpc_hoa').value);
var vacancyRate = parseFloat(document.getElementById('rpc_vacancy').value);
var maintRate = parseFloat(document.getElementById('rpc_maintenance').value);
// Validation
if (isNaN(price) || isNaN(rentIncome) || price 0) {
monthlyMortgage = loanAmount *
(monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) /
(Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
} else {
monthlyMortgage = loanAmount / numberOfPayments;
}
// 3. Calculate Monthly Expenses (Operating Expenses)
// Vacancy and Maintenance are calculated as percentages of gross rent
var monthlyVacancy = rentIncome * (vacancyRate / 100);
var monthlyMaint = rentIncome * (maintRate / 100);
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var totalMonthlyExpenses = monthlyTax + monthlyIns + monthlyHOA + monthlyVacancy + monthlyMaint;
// 4. Calculate Results
var monthlyCashFlow = rentIncome – monthlyMortgage – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
var totalInvested = downPayment + closingCosts;
// Net Operating Income (NOI) = Income – Operating Expenses (Excluding Mortgage)
var monthlyNOI = rentIncome – totalMonthlyExpenses;
var annualNOI = monthlyNOI * 12;
var capRate = (annualNOI / price) * 100;
var cashOnCash = (annualCashFlow / totalInvested) * 100;
// 5. Update DOM
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
});
document.getElementById('res_gross_income').innerText = formatter.format(rentIncome);
document.getElementById('res_mortgage').innerText = formatter.format(monthlyMortgage);
document.getElementById('res_expenses').innerText = formatter.format(totalMonthlyExpenses);
var cashFlowEl = document.getElementById('res_cashflow');
cashFlowEl.innerText = formatter.format(monthlyCashFlow);
if(monthlyCashFlow < 0) {
cashFlowEl.classList.add('rpc-negative');
cashFlowEl.classList.remove('rpc-highlight');
} else {
cashFlowEl.classList.remove('rpc-negative');
cashFlowEl.classList.add('rpc-highlight');
}
document.getElementById('res_noi').innerText = formatter.format(annualNOI);
document.getElementById('res_cap_rate').innerText = capRate.toFixed(2) + "%";
document.getElementById('res_total_invested').innerText = formatter.format(totalInvested);
var cocEl = document.getElementById('res_coc');
cocEl.innerText = cashOnCash.toFixed(2) + "%";
if(cashOnCash < 0) {
cocEl.classList.add('rpc-negative');
cocEl.classList.remove('rpc-highlight');
} else {
cocEl.classList.remove('rpc-negative');
cocEl.classList.add('rpc-highlight');
}
// Show results
document.getElementById('rpc-results').style.display = 'block';
}
How to Analyze a Rental Property Investment
Investing in real estate is a powerful way to build wealth, but simply buying a property doesn't guarantee profit. To ensure a rental property is a sound investment, you must analyze the numbers objectively. This Rental Property Cash Flow Calculator helps you determine the viability of a deal by breaking down income, expenses, and returns.
Key Metrics Explained
1. Net Operating Income (NOI)
NOI is a fundamental calculation in real estate. It represents the profitability of a property before adding any debt servicing (mortgage payments). The formula is:
NOI = Gross Rental Income – Operating Expenses
Operating expenses include taxes, insurance, maintenance, and vacancy allowances, but exclude mortgage principal and interest payments.
2. Cash Flow
This is the money left in your pocket every month after all bills, including the mortgage, are paid. Positive cash flow ensures the property pays for itself and provides passive income. The formula is:
Cash Flow = NOI – Mortgage Payment
3. Cash on Cash Return (CoC)
This metric measures the return on the actual cash you invested (down payment + closing costs), rather than the total value of the property. It is essentially the interest rate you are earning on your money. A CoC return of 8-12% is often considered a solid target for rental investors.
Cap Rate helps you compare the profitability of different properties irrespective of how they are financed. It represents the potential return on an investment if you paid all cash.
Cap Rate = (Annual NOI / Purchase Price) × 100
Estimating Expenses Correctly
New investors often overestimate cash flow by underestimating expenses. Always account for:
Vacancy: Properties won't be rented 365 days a year. A 5-8% vacancy rate is a safe conservative estimate.
Maintenance: Things break. Setting aside 5-10% of monthly rent for repairs ensures you aren't caught off guard by a broken water heater or leaky roof.
CapEx (Capital Expenditures): While not explicitly a monthly bill, big-ticket items like roof replacements should be budgeted for over time.
Use this calculator to adjust these variables and see how they impact your bottom line before you sign on the dotted line.