.rp-calculator-wrapper {
max-width: 800px;
margin: 0 auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
}
.rp-calc-box {
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
padding: 25px;
margin-bottom: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.rp-calc-title {
text-align: center;
margin-bottom: 25px;
color: #2c3e50;
font-size: 24px;
font-weight: 700;
}
.rp-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.rp-grid {
grid-template-columns: 1fr;
}
}
.rp-input-group {
margin-bottom: 15px;
}
.rp-input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 14px;
color: #555;
}
.rp-input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.rp-input-group input:focus {
border-color: #3498db;
outline: none;
}
.rp-section-header {
grid-column: 1 / -1;
font-size: 18px;
font-weight: bold;
color: #2c3e50;
margin-top: 10px;
margin-bottom: 10px;
border-bottom: 2px solid #3498db;
padding-bottom: 5px;
}
.rp-btn {
grid-column: 1 / -1;
background-color: #3498db;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.3s;
margin-top: 10px;
}
.rp-btn:hover {
background-color: #2980b9;
}
.rp-results {
margin-top: 25px;
background: #fff;
border: 1px solid #eee;
border-radius: 6px;
padding: 20px;
display: none;
}
.rp-result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #f0f0f0;
}
.rp-result-row:last-child {
border-bottom: none;
}
.rp-result-label {
color: #666;
font-weight: 500;
}
.rp-result-value {
font-weight: 700;
color: #2c3e50;
}
.rp-highlight {
color: #27ae60;
font-size: 1.1em;
}
.rp-highlight-neg {
color: #c0392b;
font-size: 1.1em;
}
.rp-content {
margin-top: 40px;
}
.rp-content h2 {
color: #2c3e50;
border-bottom: 1px solid #eee;
padding-bottom: 10px;
margin-top: 30px;
}
.rp-content p {
margin-bottom: 15px;
}
.rp-content ul {
margin-bottom: 20px;
padding-left: 20px;
}
.rp-content li {
margin-bottom: 8px;
}
function calculateRentalResults() {
// Get inputs
var price = parseFloat(document.getElementById('purchasePrice').value) || 0;
var closing = parseFloat(document.getElementById('closingCosts').value) || 0;
var downPercent = parseFloat(document.getElementById('downPaymentPercent').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value) || 0;
var years = parseFloat(document.getElementById('loanTerm').value) || 0;
var rent = parseFloat(document.getElementById('monthlyRent').value) || 0;
var vacancyRate = parseFloat(document.getElementById('vacancyRate').value) || 0;
var tax = parseFloat(document.getElementById('propertyTax').value) || 0;
var ins = parseFloat(document.getElementById('insurance').value) || 0;
var hoa = parseFloat(document.getElementById('hoaFees').value) || 0;
var maint = parseFloat(document.getElementById('maintenance').value) || 0;
var mgmt = parseFloat(document.getElementById('mgmtFee').value) || 0;
// Calculations
// 1. Initial Investment
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var totalCashInvested = downPaymentAmount + closing;
// 2. Mortgage Payment (Principal + Interest)
// M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = years * 12;
var mortgagePayment = 0;
if (monthlyRate > 0) {
mortgagePayment = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
mortgagePayment = loanAmount / numberOfPayments;
}
// 3. Income
var vacancyAmount = rent * (vacancyRate / 100);
var effectiveIncome = rent – vacancyAmount;
// 4. Expenses
var totalMonthlyExpenses = tax + ins + hoa + maint + mgmt;
// 5. Net Operating Income (NOI)
var monthlyNOI = effectiveIncome – totalMonthlyExpenses;
var annualNOI = monthlyNOI * 12;
// 6. Cash Flow
var monthlyCashFlow = monthlyNOI – mortgagePayment;
var annualCashFlow = monthlyCashFlow * 12;
// 7. Returns
var capRate = 0;
if (price > 0) {
capRate = (annualNOI / price) * 100;
}
var cocReturn = 0;
if (totalCashInvested > 0) {
cocReturn = (annualCashFlow / totalCashInvested) * 100;
}
// Formatting Function
var fmtMoney = function(num) {
return '$' + num.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
};
var fmtPercent = function(num) {
return num.toFixed(2) + '%';
};
// Display Results
var resCashFlowEl = document.getElementById('resCashFlow');
resCashFlowEl.innerText = fmtMoney(monthlyCashFlow);
// Color coding for cash flow
if (monthlyCashFlow >= 0) {
resCashFlowEl.className = 'rp-result-value rp-highlight';
} else {
resCashFlowEl.className = 'rp-result-value rp-highlight-neg';
}
document.getElementById('resNOI').innerText = fmtMoney(monthlyNOI);
document.getElementById('resTotalInvestment').innerText = fmtMoney(totalCashInvested);
document.getElementById('resMortgage').innerText = fmtMoney(mortgagePayment);
var cocEl = document.getElementById('resCoC');
cocEl.innerText = fmtPercent(cocReturn);
if (cocReturn >= 0) {
cocEl.className = 'rp-result-value rp-highlight';
} else {
cocEl.className = 'rp-result-value rp-highlight-neg';
}
document.getElementById('resCapRate').innerText = fmtPercent(capRate);
// Show results container
document.getElementById('rpResults').style.display = 'block';
}
Rental Property Calculator
Purchase Information
Loan Details
Rental Income
Monthly Expenses
Financial Analysis
Monthly Cash Flow
Net Operating Income (NOI) / Month
Total Cash Needed (Down + Closing)
Monthly Mortgage Payment
Cash on Cash Return (Annual)
Cap Rate
Understanding Rental Property Analysis
Investing in real estate is one of the most reliable ways to build wealth, but analyzing a deal correctly is critical to success. This Rental Property Cash Flow Calculator helps investors determine the profitability of a potential purchase by analyzing income, expenses, financing costs, and return metrics.
What is Cash Flow?
Cash flow is the profit you bring in each month after all operating expenses and mortgage payments have been made. Positive cash flow means the property is putting money in your pocket, while negative cash flow means you are paying out of pocket to hold the property.
To calculate cash flow, the formula is generally:
- Gross Income (Rent) – Vacancy = Effective Gross Income
- Effective Gross Income – Operating Expenses = Net Operating Income (NOI)
- NOI – Debt Service (Mortgage) = Cash Flow
Key Metrics for Investors
Cash on Cash Return (CoC)
Cash on Cash return measures the annual return on the actual cash you invested, rather than the total purchase price. This is crucial because it accounts for leverage (loans). It is calculated by dividing your annual pre-tax cash flow by the total cash invested (Down Payment + Closing Costs + Rehab Costs).
Example: If you invest $50,000 cash and generate $5,000 in positive cash flow per year, your CoC return is 10%.
Cap Rate (Capitalization Rate)
The Cap Rate indicates the rate of return on a real estate investment property based on the income that the property is expected to generate, assuming the property was bought with cash (no loan). It allows you to compare properties regardless of financing.
Formula: Net Operating Income (Annual) / Current Market Value.
How to Use This Calculator
- Purchase Price: Enter the negotiated price of the property.
- Loan Details: Input your down payment percentage, interest rate, and loan term (usually 30 years).
- Rental Income: Estimate the monthly rent based on comparable properties in the area. Don't forget to account for vacancy (typically 5-10%).
- Expenses: Be honest about costs. Include taxes, insurance, HOA fees, maintenance reserves, and property management fees if you aren't self-managing.
Use these metrics to decide if a property aligns with your investment goals. Many investors look for positive cash flow from day one and a Cash on Cash return of at least 8-12%.