.rp-calculator-container {
max-width: 800px;
margin: 20px auto;
padding: 30px;
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
.rp-calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.rp-calc-grid {
grid-template-columns: 1fr;
}
}
.rp-input-group {
margin-bottom: 15px;
}
.rp-input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #333;
font-size: 14px;
}
.rp-input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box;
font-size: 16px;
}
.rp-input-group input:focus {
border-color: #0073aa;
outline: none;
}
.rp-btn {
grid-column: 1 / -1;
background-color: #0073aa;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 5px;
cursor: pointer;
margin-top: 10px;
transition: background 0.3s;
width: 100%;
}
.rp-btn:hover {
background-color: #005177;
}
.rp-results {
grid-column: 1 / -1;
margin-top: 25px;
padding: 20px;
background: #fff;
border: 1px solid #ddd;
border-radius: 5px;
display: none;
}
.rp-result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.rp-result-row:last-child {
border-bottom: none;
}
.rp-result-label {
font-weight: 500;
color: #555;
}
.rp-result-value {
font-weight: 700;
color: #000;
}
.rp-positive {
color: #27ae60;
}
.rp-negative {
color: #c0392b;
}
.rp-highlight {
background-color: #f0f8ff;
padding: 10px;
border-radius: 4px;
margin-top: 5px;
}
.article-content {
max-width: 800px;
margin: 40px auto;
font-family: inherit;
line-height: 1.6;
color: #333;
}
.article-content h2 {
margin-top: 30px;
color: #2c3e50;
}
.article-content h3 {
color: #34495e;
}
.article-content ul {
margin-left: 20px;
}
function calculateCashFlow() {
// 1. Get Inputs
var price = parseFloat(document.getElementById('rpPurchasePrice').value);
var downPercent = parseFloat(document.getElementById('rpDownPayment').value);
var interestRate = parseFloat(document.getElementById('rpInterestRate').value);
var termYears = parseFloat(document.getElementById('rpLoanTerm').value);
var rent = parseFloat(document.getElementById('rpMonthlyRent').value);
var taxYearly = parseFloat(document.getElementById('rpPropertyTax').value);
var insuranceYearly = parseFloat(document.getElementById('rpInsurance').value);
var hoaMonthly = parseFloat(document.getElementById('rpHOA').value);
var vacancyPercent = parseFloat(document.getElementById('rpVacancy').value);
var capexPercent = parseFloat(document.getElementById('rpCapex').value);
// Validation
if (isNaN(price) || isNaN(rent) || isNaN(interestRate) || price 0 && loanAmount > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, totalPayments)) / (Math.pow(1 + monthlyRate, totalPayments) – 1);
} else if (loanAmount > 0 && interestRate === 0) {
monthlyMortgage = loanAmount / totalPayments;
}
// 3. Operating Expense Calculations
var monthlyTax = taxYearly / 12;
var monthlyInsurance = insuranceYearly / 12;
var vacancyCost = rent * (vacancyPercent / 100);
var capexCost = rent * (capexPercent / 100);
var totalMonthlyOperatingExpenses = monthlyTax + monthlyInsurance + hoaMonthly + vacancyCost + capexCost;
var totalMonthlyExpenses = monthlyMortgage + totalMonthlyOperatingExpenses;
// 4. Profit Metrics
var monthlyCashFlow = rent – totalMonthlyExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// Net Operating Income (NOI) = Income – Operating Expenses (Excluding Debt Service)
var annualOperatingExpenses = totalMonthlyOperatingExpenses * 12;
var annualIncome = rent * 12;
var annualNOI = annualIncome – annualOperatingExpenses;
// Cap Rate = NOI / Price
var capRate = (annualNOI / price) * 100;
// Cash on Cash Return = Annual Cash Flow / Total Cash Invested
// Estimating Closing Costs at 3% of price for realistic CoC
var closingCosts = price * 0.03;
var totalCashInvested = downPaymentAmount + closingCosts;
var cocReturn = 0;
if (totalCashInvested > 0) {
cocReturn = (annualCashFlow / totalCashInvested) * 100;
}
// 5. Display Results
document.getElementById('resMortgage').innerText = "$" + monthlyMortgage.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resTotalExpenses').innerText = "$" + totalMonthlyExpenses.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
var cashFlowEl = document.getElementById('resCashFlow');
cashFlowEl.innerText = "$" + monthlyCashFlow.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Styling positive/negative cash flow
if (monthlyCashFlow >= 0) {
cashFlowEl.className = "rp-result-value rp-positive";
} else {
cashFlowEl.className = "rp-result-value rp-negative";
}
document.getElementById('resNOI').innerText = "$" + annualNOI.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resCapRate').innerText = capRate.toFixed(2) + "%";
document.getElementById('resCoC').innerText = cocReturn.toFixed(2) + "%";
document.getElementById('rpResults').style.display = "block";
}
Rental Property Cash Flow Calculator
Investing in real estate is one of the most reliable ways to build long-term wealth, but not every property is a good investment. The difference between a profitable asset and a financial burden often comes down to one metric: Cash Flow. Our Rental Property Cash Flow Calculator is designed to help investors accurately predict the monthly income a property will generate after all expenses are paid.
How to Calculate Rental Property Cash Flow
To determine if a rental property is a sound investment, you must analyze the relationship between income and expenses. Here is the step-by-step logic used in this calculator:
1. Gross Income
This is the total money you expect to collect from tenants. While this is primarily rent, it can also include laundry fees, parking fees, or pet rent. Be realistic with your rental estimates by comparing similar properties in the area (comps).
2. Operating Expenses
Many new investors make the mistake of only calculating the mortgage payment. A true cash flow analysis must include:
- Property Taxes & Insurance: Recurring annual costs that should be broken down monthly.
- Vacancy Rate: You won't have a tenant 100% of the time. We recommend allocating 5-8% of the rent to cover periods of vacancy.
- Repairs & CapEx: Even if the house is new, things break. Allocating 5-10% for maintenance (Repairs) and big-ticket items like roof replacement (Capital Expenditures) is crucial for long-term accuracy.
- HOA Fees: If the property is in a Homeowners Association, this monthly fee is mandatory and non-negotiable.
3. Net Operating Income (NOI)
This is a critical metric calculated by subtracting Operating Expenses from Gross Income. Note that NOI does not include mortgage payments. It represents the profitability of the property itself, regardless of how it is financed.
4. Debt Service (Mortgage)
Unless you are buying in cash, you will have a monthly mortgage payment consisting of Principal and Interest (P&I). This is subtracted from the NOI.
5. Cash Flow
Finally, the formula for cash flow is:
Cash Flow = Gross Income – (Operating Expenses + Debt Service).
Positive cash flow means the property is putting money in your pocket every month.
Understanding Key Investment Metrics
This calculator provides two advanced metrics to help you compare investments:
Cap Rate (Capitalization Rate): Calculated as NOI / Purchase Price. It measures the natural rate of return of the property if you bought it in cash. A higher Cap Rate generally indicates a better return, though often comes with higher risk.
Cash on Cash (CoC) Return: Calculated as Annual Cash Flow / Total Cash Invested. This tells you how hard your actual money (Down Payment + Closing Costs) is working for you. For example, if you invest $50,000 to buy a house and it generates $5,000 a year in cash flow, your CoC return is 10%.
Example Scenario
Imagine you purchase a property for $250,000 with 20% down. You rent it for $2,200/month.
After paying the mortgage ($1,264), taxes ($250), insurance ($100), and setting aside reserves for vacancy and repairs ($330), your total expenses might be around $1,944.
Result: You are left with approximately $256/month in positive cash flow. This calculator helps you tweak the numbers (like offer price or rent) to see how they impact your bottom line.