Determine the potential profitability of an investment property by calculating its estimated monthly and annual cash flow. This tool helps real estate investors analyze income against operating expenses and debt service.
1. Income
2. Recurring Operating Expenses
3. Debt Service
Analysis Results
Gross Monthly Income:
$0.00
Vacancy Loss:
-$0.00
Effective Gross Income:
$0.00
Total Operating Expenses:
-$0.00
Monthly Net Operating Income (NOI):
$0.00
Monthly Mortgage Debt Payment:
-$0.00
Estimated Monthly Cash Flow:
$0.00
Estimated Annual Cash Flow:
$0.00
function calculateCashFlow() {
// 1. Get Income Inputs
var monthlyRent = parseFloat(document.getElementById('rpcf_monthlyRent').value) || 0;
var otherIncome = parseFloat(document.getElementById('rpcf_otherIncome').value) || 0;
var vacancyRate = parseFloat(document.getElementById('rpcf_vacancyRate').value) || 0;
// 2. Get Operating Expense Inputs
var annualTaxes = parseFloat(document.getElementById('rpcf_annualTaxes').value) || 0;
var annualInsurance = parseFloat(document.getElementById('rpcf_annualInsurance').value) || 0;
var managementFeePercent = parseFloat(document.getElementById('rpcf_managementFee').value) || 0;
var maintenanceReserve = parseFloat(document.getElementById('rpcf_maintenance').value) || 0;
var otherExp = parseFloat(document.getElementById('rpcf_otherExp').value) || 0;
// 3. Get Debt Input
var mortgagePayment = parseFloat(document.getElementById('rpcf_mortgagePayment').value) || 0;
// — Calculations —
// Income Calculations
var grossPotentialIncome = monthlyRent + otherIncome;
var vacancyLoss = grossPotentialIncome * (vacancyRate / 100);
var effectiveGrossIncome = grossPotentialIncome – vacancyLoss;
// Expense Calculations
var monthlyTaxes = annualTaxes / 12;
var monthlyInsurance = annualInsurance / 12;
var managementFeeAmount = effectiveGrossIncome * (managementFeePercent / 100);
var totalMonthlyExpenses = monthlyTaxes + monthlyInsurance + managementFeeAmount + maintenanceReserve + otherExp;
// NOI Calculation
var monthlyNOI = effectiveGrossIncome – totalMonthlyExpenses;
// Cash Flow Calculation
var monthlyCashFlow = monthlyNOI – mortgagePayment;
var annualCashFlow = monthlyCashFlow * 12;
// — Display Results —
document.getElementById('rpcf_res_grossIncome').innerHTML = '$' + grossPotentialIncome.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('rpcf_res_vacancyLoss').innerHTML = '-$' + vacancyLoss.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('rpcf_res_effectiveIncome').innerHTML = '$' + effectiveGrossIncome.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('rpcf_res_totalExpenses').innerHTML = '-$' + totalMonthlyExpenses.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('rpcf_res_noi').innerHTML = '$' + monthlyNOI.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('rpcf_res_debt').innerHTML = '-$' + mortgagePayment.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('rpcf_res_monthlyCashFlow').innerHTML = '$' + monthlyCashFlow.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('rpcf_res_annualCashFlow').innerHTML = '$' + annualCashFlow.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
// Show results container
document.getElementById('rpcf_results').style.display = 'block';
}
Understanding Rental Property Cash Flow
For real estate investors, "cash flow" is the net amount of cash moving in and out of a rental property business. Positive cash flow means the property is generating more income than it costs to operate and finance, while negative cash flow means you are paying out of pocket to keep the property running.
How This Calculator Works
This calculator uses a standard real estate analysis approach to determine your pre-tax cash flow. It breaks down the calculation into three main parts:
Gross Income: The total potential income from rent and other sources, adjusted downwards for expected vacancy losses.
Operating Expenses: The day-to-day costs of running the property, such as taxes, insurance, management fees, and repairs. Note that mortgage payments are not included here.
Debt Service: Your monthly mortgage payment (principal and interest).
Key Metrics Defined
Net Operating Income (NOI): This is a critical metric in real estate. It equals all revenue from the property minus all necessary operating expenses. NOI measures the property's ability to generate income income independent of its financing structure.
Cash Flow: This is what ends up in your pocket. It is calculated by taking the NOI and subtracting the mortgage payment (debt service).
Realistic Example
Let's say you buy a single-family home to rent out.
You charge $1,800 per month in rent.
You estimate a 5% vacancy rate to account for turnover.
Your annual taxes are $3,000 ($250/mo) and insurance is $1,200 ($100/mo).
You set aside $150 a month for repairs and pay a manager 8%.
Your mortgage payment is $900 per month.
Using the calculator above, your Effective Gross Income would be $1,710 (after vacancy loss). Your total Operating Expenses would be roughly $636.80. Your NOI would be $1,073.20. After paying the $900 mortgage, your estimated Monthly Cash Flow would be a positive $173.20.