.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-container {
background: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 30px;
margin-bottom: 40px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.calc-header {
text-align: center;
margin-bottom: 25px;
color: #2c3e50;
}
.input-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.input-grid {
grid-template-columns: 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 0.9rem;
color: #495057;
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 1rem;
box-sizing: border-box;
}
.input-group input:focus {
border-color: #4dabf7;
outline: none;
box-shadow: 0 0 0 3px rgba(77, 171, 247, 0.2);
}
.calc-btn {
grid-column: 1 / -1;
background-color: #228be6;
color: white;
border: none;
padding: 15px;
font-size: 1.1rem;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.2s;
width: 100%;
margin-top: 10px;
}
.calc-btn:hover {
background-color: #1c7ed6;
}
.results-box {
grid-column: 1 / -1;
background: #fff;
border: 1px solid #dee2e6;
border-radius: 6px;
padding: 20px;
margin-top: 20px;
display: none;
}
.results-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 15px;
}
.result-item {
text-align: center;
padding: 10px;
background: #f1f3f5;
border-radius: 4px;
}
.result-label {
display: block;
font-size: 0.85rem;
color: #868e96;
text-transform: uppercase;
letter-spacing: 0.5px;
margin-bottom: 5px;
}
.result-value {
font-size: 1.25rem;
font-weight: 700;
color: #212529;
}
.main-result {
grid-column: 1 / -1;
background: #e7f5ff;
color: #1864ab;
}
.content-section h2 {
color: #2c3e50;
border-bottom: 2px solid #e9ecef;
padding-bottom: 10px;
margin-top: 40px;
}
.content-section h3 {
color: #34495e;
margin-top: 25px;
}
.content-section ul {
padding-left: 20px;
}
.content-section li {
margin-bottom: 10px;
}
.example-box {
background: #fff9db;
padding: 15px;
border-left: 4px solid #fab005;
margin: 20px 0;
}
function calculateRental() {
// Get Inputs
var price = parseFloat(document.getElementById("purchasePrice").value);
var downPercent = parseFloat(document.getElementById("downPayment").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var termYears = parseFloat(document.getElementById("loanTerm").value);
var closingCosts = parseFloat(document.getElementById("closingCosts").value);
var rent = parseFloat(document.getElementById("monthlyRent").value);
var vacancyPercent = parseFloat(document.getElementById("vacancyRate").value);
var expenses = parseFloat(document.getElementById("monthlyExpenses").value);
// Validation
if (isNaN(price) || isNaN(downPercent) || isNaN(interestRate) || isNaN(termYears) || isNaN(rent)) {
alert("Please enter valid numbers for all fields.");
return;
}
// Calculations
var downPaymentAmount = price * (downPercent / 100);
var loanAmount = price – downPaymentAmount;
var totalCashInvested = downPaymentAmount + closingCosts;
// Mortgage Calculation (Principal + Interest)
// M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = termYears * 12;
var monthlyMortgage = 0;
if (interestRate > 0) {
monthlyMortgage = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else {
monthlyMortgage = loanAmount / numberOfPayments;
}
// Income Calculations
var vacancyLoss = rent * (vacancyPercent / 100);
var effectiveGrossIncome = rent – vacancyLoss;
// Operating Calculations
var monthlyNOI = effectiveGrossIncome – expenses;
var annualNOI = monthlyNOI * 12;
// Cash Flow
var monthlyCashFlow = monthlyNOI – monthlyMortgage;
var annualCashFlow = monthlyCashFlow * 12;
// Returns
var cashOnCash = 0;
if (totalCashInvested > 0) {
cashOnCash = (annualCashFlow / totalCashInvested) * 100;
}
var capRate = (annualNOI / price) * 100;
// Display Results
document.getElementById("results").style.display = "block";
document.getElementById("outCashFlow").innerHTML = formatCurrency(monthlyCashFlow);
document.getElementById("outCashFlow").style.color = monthlyCashFlow >= 0 ? "#2f9e44" : "#e03131";
document.getElementById("outCoC").innerHTML = cashOnCash.toFixed(2) + "%";
document.getElementById("outCoC").style.color = cashOnCash >= 0 ? "#2f9e44" : "#e03131";
document.getElementById("outCapRate").innerHTML = capRate.toFixed(2) + "%";
document.getElementById("outMortgage").innerHTML = formatCurrency(monthlyMortgage);
document.getElementById("outNOI").innerHTML = formatCurrency(monthlyNOI);
document.getElementById("outInvested").innerHTML = formatCurrency(totalCashInvested);
}
function formatCurrency(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
Rental Property Cash Flow Calculator
Monthly Cash Flow
$0.00
Cash on Cash Return
0.00%
Cap Rate
0.00%
Monthly Mortgage
$0.00
Monthly NOI
$0.00
Total Cash Invested
$0.00
Understanding Rental Property Cash Flow
Investing in real estate is a powerful way to build wealth, but the key to a successful investment is positive cash flow. This Rental Property Cash Flow Calculator helps investors analyze potential deals by breaking down income, expenses, and financing costs to determine the true profitability of a property.
What is Cash Flow?
Cash flow is the net amount of money moving in and out of your rental business. In simple terms, it is the money left over from your monthly rent after all expenses (mortgage, taxes, insurance, repairs) have been paid. A positive cash flow means the property pays for itself and generates profit.
Key Metrics Explained
- NOI (Net Operating Income): The total income generated by the property minus all necessary operating expenses. Note that NOI excludes mortgage payments. This is a pure measure of the asset's efficiency.
- Cap Rate (Capitalization Rate): Calculated as
(Annual NOI / Purchase Price) × 100. It represents the potential return on investment if the property were bought with all cash. It helps compare properties regardless of financing. - Cash on Cash Return: Calculated as
(Annual Pre-Tax Cash Flow / Total Cash Invested) × 100. This measures the return on the actual cash you put into the deal (down payment + closing costs). It is often considered the most important metric for leveraged investors.
Real World Example
Imagine you purchase a property for $200,000. You put 20% down ($40,000) and pay $4,000 in closing costs.
You rent the property for $2,000/month. After accounting for a 5% vacancy rate and $500 in monthly operating expenses (taxes, insurance, maintenance), your Net Operating Income (NOI) is roughly $1,400.
If your mortgage payment is roughly $1,011 (at 6.5% interest), your Monthly Cash Flow would be approx $389. Your Cash on Cash return would be around 10.6% per year, which is a solid return for a rental investment.
Factors That Kill Cash Flow
When analyzing a deal, pay close attention to the "hidden" costs that can turn a good deal bad:
- Vacancy Rates: Always account for the time the property sits empty. A 5-8% vacancy allowance is standard in many markets.
- Capital Expenditures (CapEx): Big-ticket items like a new roof or HVAC system. While not a monthly cost, you should budget for them monthly to avoid shock.
- Property Management: If you don't plan to manage the property yourself, expect to pay 8-10% of the monthly rent to a manager.
How to Use This Calculator
To get the most accurate results, input the purchase price and your financing details. Be realistic with your Operating Expenses; many new investors underestimate the cost of repairs and maintenance. A common rule of thumb is the "50% Rule," suggesting that operating expenses often average 50% of gross income over time, though specific inputs are always better.