.rental-calculator-wrapper {
max-width: 800px;
margin: 0 auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
color: #333;
line-height: 1.6;
}
.calc-box {
background: #f9f9f9;
border: 1px solid #e1e1e1;
border-radius: 8px;
padding: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
margin-bottom: 40px;
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.calc-grid {
grid-template-columns: 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 14px;
color: #555;
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box; /* Ensure padding doesn't affect width */
}
.input-group input:focus {
border-color: #0073aa;
outline: none;
box-shadow: 0 0 0 2px rgba(0,115,170,0.2);
}
.section-title {
grid-column: 1 / -1;
font-size: 18px;
font-weight: bold;
margin-top: 10px;
margin-bottom: 10px;
color: #0073aa;
border-bottom: 2px solid #eee;
padding-bottom: 5px;
}
.calc-btn {
grid-column: 1 / -1;
background: #0073aa;
color: white;
border: none;
padding: 15px 30px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background 0.2s;
text-align: center;
margin-top: 10px;
}
.calc-btn:hover {
background: #005177;
}
.results-area {
grid-column: 1 / -1;
background: #fff;
border: 1px solid #ddd;
border-radius: 6px;
padding: 20px;
margin-top: 20px;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.result-row:last-child {
border-bottom: none;
}
.result-label {
color: #666;
}
.result-value {
font-weight: bold;
font-size: 18px;
}
.highlight-result {
color: #27ae60;
font-size: 24px;
}
.content-area h2 {
font-size: 28px;
margin-top: 40px;
color: #2c3e50;
}
.content-area h3 {
font-size: 22px;
margin-top: 30px;
color: #34495e;
}
.content-area p {
margin-bottom: 15px;
font-size: 17px;
}
.content-area ul {
margin-bottom: 20px;
padding-left: 20px;
}
.content-area li {
margin-bottom: 10px;
font-size: 17px;
}
.metric-card {
background: #f1f8ff;
border-left: 4px solid #0073aa;
padding: 15px;
margin: 20px 0;
}
function calculateRentalROI() {
// Get Input Values
var price = parseFloat(document.getElementById('rp_purchase_price').value) || 0;
var downPayment = parseFloat(document.getElementById('rp_down_payment').value) || 0;
var closingCosts = parseFloat(document.getElementById('rp_closing_costs').value) || 0;
var rehabCosts = parseFloat(document.getElementById('rp_rehab_costs').value) || 0;
var interestRate = parseFloat(document.getElementById('rp_interest_rate').value) || 0;
var loanYears = parseFloat(document.getElementById('rp_loan_term').value) || 0;
var monthlyRent = parseFloat(document.getElementById('rp_monthly_rent').value) || 0;
var annualTax = parseFloat(document.getElementById('rp_property_tax').value) || 0;
var annualInsurance = parseFloat(document.getElementById('rp_insurance').value) || 0;
var monthlyHOA = parseFloat(document.getElementById('rp_hoa').value) || 0;
var vacancyRate = parseFloat(document.getElementById('rp_vacancy').value) || 0;
var capexRate = parseFloat(document.getElementById('rp_capex').value) || 0;
// 1. Calculate Mortgage Payment
var loanAmount = price – downPayment;
var monthlyInterest = (interestRate / 100) / 12;
var numberOfPayments = loanYears * 12;
var monthlyMortgage = 0;
if (loanAmount > 0 && interestRate > 0) {
monthlyMortgage = loanAmount * (monthlyInterest * Math.pow(1 + monthlyInterest, numberOfPayments)) / (Math.pow(1 + monthlyInterest, numberOfPayments) – 1);
} else if (loanAmount > 0 && interestRate === 0) {
monthlyMortgage = loanAmount / numberOfPayments;
}
// 2. Calculate Operating Expenses
var monthlyTax = annualTax / 12;
var monthlyInsurance = annualInsurance / 12;
var vacancyCost = monthlyRent * (vacancyRate / 100);
var capexCost = monthlyRent * (capexRate / 100);
// Total Monthly Operating Expenses (Excluding Mortgage)
var totalMonthlyExpenses = monthlyTax + monthlyInsurance + monthlyHOA + vacancyCost + capexCost;
// 3. Calculate NOI (Net Operating Income)
// Effective Gross Income = Rent – Vacancy (Vacancy is usually subtracted from Gross, but here we treat it as expense bucket for simplicity or subtraction. Let's stick to standard: Gross – Vacancy = Effective Gross. Then Effective – Operating Expenses = NOI.
// In my variables above, I calculated vacancyCost.
// So: NOI = (MonthlyRent – VacancyCost) – (Tax + Ins + HOA + Capex/Maint).
var noiMonthly = (monthlyRent – vacancyCost) – (monthlyTax + monthlyInsurance + monthlyHOA + capexCost);
var noiAnnual = noiMonthly * 12;
// 4. Calculate Cash Flow
var monthlyCashFlow = noiMonthly – monthlyMortgage;
var annualCashFlow = monthlyCashFlow * 12;
// 5. Calculate Investment Metrics
var totalCashInvested = downPayment + closingCosts + rehabCosts;
var cocReturn = 0;
if (totalCashInvested > 0) {
cocReturn = (annualCashFlow / totalCashInvested) * 100;
}
var capRate = 0;
if (price > 0) {
capRate = (noiAnnual / price) * 100;
}
// Display Results
// Format currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
});
document.getElementById('res_mortgage').innerText = formatter.format(monthlyMortgage);
// Show total expenses including mortgage for the user? Usually investors want OpEx separate.
// Let's show Total Outflow (Mortgage + Expenses).
// But the label says "Total Monthly Expenses". In real estate this usually means OpEx. Let's stick to OpEx + Mortgage for a "Total Cost" view or just OpEx?
// Better UX: Show OpEx + Mortgage sum makes sense for "how much leaves my bank account".
// However, to align with the NOI calculation display, I will show OpEx.
document.getElementById('res_expenses').innerText = formatter.format(totalMonthlyExpenses);
document.getElementById('res_noi').innerText = formatter.format(noiMonthly);
document.getElementById('res_cashflow').innerText = formatter.format(monthlyCashFlow);
document.getElementById('res_coc').innerText = cocReturn.toFixed(2) + '%';
document.getElementById('res_caprate').innerText = capRate.toFixed(2) + '%';
// Coloring
var cashFlowElem = document.getElementById('res_cashflow');
if(monthlyCashFlow >= 0) {
cashFlowElem.style.color = '#27ae60'; // Green
} else {
cashFlowElem.style.color = '#c0392b'; // Red
}
// Show container
document.getElementById('rp_results').style.display = 'block';
}
Rental Property ROI & Cash Flow Calculator
Purchase Information
Loan Details
Income & Expenses
Investment Analysis
Monthly Mortgage Payment (P&I):
$0.00
Total Monthly Expenses:
$0.00
Net Operating Income (NOI) / Mo:
$0.00
Monthly Cash Flow:
$0.00
Cash on Cash Return (CoC):
0.00%
Cap Rate:
0.00%
How to Analyze a Rental Property Investment
Investing in real estate is one of the most reliable ways to build wealth, but simply buying a property and renting it out doesn't guarantee a profit. To succeed, investors must rigorously analyze the numbers before signing a contract. This Rental Property Calculator helps you determine the viability of a potential deal by breaking down cash flow, Cash on Cash (CoC) return, and Cap Rate.
Key Metric: Cash Flow
Cash flow is the net amount of money moving in or out of the investment after all expenses and mortgage payments are made. Positive cash flow means the property is putting money in your pocket every month.
Understanding the Inputs
Accurate results depend on accurate data inputs. Here is what you need to know about the fields above:
- Purchase Price & Down Payment: The agreed price of the home and the cash you are putting down upfront. Standard investment loans often require 20-25% down.
- Closing & Rehab Costs: Don't forget the "hidden" costs. Closing costs typically run 2-5% of the purchase price, and initial repairs are cash out of pocket that increases your total initial investment.
- Vacancy Rate: No property is rented 365 days a year forever. A safe estimate is 5-8% (about 2-3 weeks of vacancy per year) to account for turnover.
- Maintenance/CapEx: Things break. Setting aside 10-15% of the rent for repairs (Maintenance) and major replacements like roofs or HVAC (Capital Expenditures) is crucial for long-term solvency.
Interpreting Your Results
Cash on Cash Return (CoC)
This is arguably the most important metric for rental investors. It measures the annual return on the actual cash you invested, not the total loan amount.
Formula: Annual Pre-Tax Cash Flow / Total Cash Invested
While "good" is subjective, many investors look for a CoC return of 8% to 12% or higher, which often outperforms the stock market while providing the added benefits of equity paydown and tax depreciation.
Net Operating Income (NOI)
NOI is the profitability of the property before adding in the mortgage financing. It helps you compare the profitability of the building itself, regardless of how you paid for it (cash vs. loan).
Cap Rate (Capitalization Rate)
Calculated as NOI / Purchase Price, the Cap Rate indicates the rate of return if you bought the property all cash. In high-demand areas, Cap Rates might be lower (3-5%), while in riskier or developing areas, they might be higher (8-10%).
Why Cash Flow Can Be Negative
If this calculator shows negative cash flow, it means the rent isn't covering the mortgage and expenses. This often happens if:
- The purchase price is too high for the local rental market.
- The down payment is too low, resulting in a massive mortgage payment.
- Operating expenses (taxes, HOA, insurance) were underestimated.
Always verify your rental estimates with local property managers or listings on platforms like Zillow or Craigslist to ensure your income assumptions are realistic.