Total Monthly Expenses (Operating + Mortgage):$0.00
Net Operating Income (NOI) (Before Mortgage):$0.00
Monthly Cash Flow:$0.00
Annual Cash Flow:$0.00
Understanding Rental Property Cash Flow
Cash flow is the lifeblood of any rental property investment. It represents the net amount of money moving into or out of your business after all expenses are paid. A positive cash flow means your property is generating profit, while negative cash flow implies the property costs you money to hold.
How to Calculate Rental Cash Flow
The formula for calculating rental property cash flow is straightforward but requires attention to detail regarding expenses:
Gross Income: The total rent collected plus any additional income (laundry, parking, etc.).
Operating Expenses: Costs required to run the property, including taxes, insurance, repairs, vacancy reserves, and property management fees.
Net Operating Income (NOI): Gross Income minus Operating Expenses (excluding mortgage payments).
Cash Flow: NOI minus Debt Service (Mortgage Payments).
Why Variable Factors Matter
Many novice investors make the mistake of calculating cash flow based solely on "Rent minus Mortgage." However, true cash flow analysis must account for:
Vacancy Rate: Properties are rarely occupied 365 days a year. A 5-8% vacancy buffer is standard industry practice.
Repairs & CapEx: Budgeting for routine maintenance and major capital expenditures (like a new roof or HVAC) is critical for long-term accuracy.
Property Management: Even if you self-manage, it is wise to account for this cost to understand the "passive" value of the investment.
Use this Rental Property Cash Flow Calculator to evaluate potential deals accurately before making an offer.
function calculateCashFlow() {
// 1. Get Input Values
var grossRent = parseFloat(document.getElementById("rp_gross_rent").value);
var otherIncome = parseFloat(document.getElementById("rp_other_income").value);
var mortgage = parseFloat(document.getElementById("rp_mortgage").value);
var insurance = parseFloat(document.getElementById("rp_insurance").value);
var taxes = parseFloat(document.getElementById("rp_taxes").value);
var hoa = parseFloat(document.getElementById("rp_hoa").value);
var vacancyRate = parseFloat(document.getElementById("rp_vacancy").value);
var repairsRate = parseFloat(document.getElementById("rp_repairs").value);
var managementRate = parseFloat(document.getElementById("rp_management").value);
// 2. Validate Inputs (Handle NaN)
if (isNaN(grossRent)) grossRent = 0;
if (isNaN(otherIncome)) otherIncome = 0;
if (isNaN(mortgage)) mortgage = 0;
if (isNaN(insurance)) insurance = 0;
if (isNaN(taxes)) taxes = 0;
if (isNaN(hoa)) hoa = 0;
if (isNaN(vacancyRate)) vacancyRate = 0;
if (isNaN(repairsRate)) repairsRate = 0;
if (isNaN(managementRate)) managementRate = 0;
// 3. Calculate Income
var totalIncome = grossRent + otherIncome;
// 4. Calculate Variable Expenses based on Gross Rent
var vacancyCost = grossRent * (vacancyRate / 100);
var repairsCost = grossRent * (repairsRate / 100);
var managementCost = grossRent * (managementRate / 100);
// 5. Calculate Total Operating Expenses (Excluding Mortgage)
var operatingExpenses = insurance + taxes + hoa + vacancyCost + repairsCost + managementCost;
// 6. Calculate NOI
var noi = totalIncome – operatingExpenses;
// 7. Calculate Total Expenses (Including Mortgage)
var totalExpenses = operatingExpenses + mortgage;
// 8. Calculate Cash Flow
var monthlyCashFlow = totalIncome – totalExpenses;
var annualCashFlow = monthlyCashFlow * 12;
// 9. Display Results
document.getElementById("rp_results_area").style.display = "block";
document.getElementById("rp_res_income").innerText = "$" + totalIncome.toFixed(2);
document.getElementById("rp_res_expenses").innerText = "$" + totalExpenses.toFixed(2);
document.getElementById("rp_res_noi").innerText = "$" + noi.toFixed(2);
var cashFlowEl = document.getElementById("rp_res_cashflow");
cashFlowEl.innerText = "$" + monthlyCashFlow.toFixed(2);
// Style positive/negative results
if (monthlyCashFlow >= 0) {
cashFlowEl.className = "rp-result-val rp-positive";
} else {
cashFlowEl.className = "rp-result-val rp-negative";
}
var annualEl = document.getElementById("rp_res_annual");
annualEl.innerText = "$" + annualCashFlow.toFixed(2);
if (annualCashFlow >= 0) {
annualEl.className = "rp-result-val rp-positive";
} else {
annualEl.className = "rp-result-val rp-negative";
}
}