Rental Property Cash Flow & Cap Rate Calculator

Calculate the net operating income, cap rate, monthly cash flow, and cash-on-cash return of a rental property based on purchase price, financing, rental income, and operating expenses.

Mathematical Audit

Rental Property Cash Flow & Cap Rate Formula

This calculator estimates the operating performance of a rental property by netting rental income against vacancy, operating expenses, and debt service, then expressing the result as a cap rate and cash-on-cash return.

Gross Potential Rent (Annual) = (Monthly Rent + Other Monthly Income) × 12
Effective Gross Income = Gross Potential Rent − (Gross Potential Rent × Vacancy Rate %)
Operating Expenses = Property Tax + Insurance + HOA + Other Expenses + Maintenance + Management Fees
Net Operating Income (NOI) = Effective Gross Income − Operating Expenses
Cap Rate (%) = (NOI ÷ Purchase Price) × 100
Annual Cash Flow = NOI − Annual Mortgage Payments (Debt Service)
Cash-on-Cash Return (%) = (Annual Cash Flow ÷ Total Cash Invested) × 100

Cap rate measures a property's unleveraged return and is widely used to compare deals regardless of financing. Cash-on-cash return measures the return on the actual cash invested (down payment + closing costs) after factoring in mortgage payments, so it is typically higher or lower than the cap rate depending on leverage. A 'good' cap rate is generally considered to be between 4% and 10% depending on market and risk profile.

Operational Guide

How to Use the Rental Property Cash Flow & Cap Rate Calculator

1

Enter the purchase price and financing details

Input the purchase price, down payment percentage, mortgage interest rate, and loan term to calculate the loan amount and monthly payment.

2

Enter monthly rental income

Add the expected monthly rent and any other income (parking, laundry, storage) plus an expected vacancy rate.

3

Enter operating expenses

Add annual property tax, insurance, HOA dues, maintenance and management percentages, and any other recurring costs.

4

Enter closing costs

Add your estimated closing costs as a percentage of the purchase price to calculate total cash invested.

5

Click Calculate

View your NOI, cap rate, monthly cash flow, annual cash flow, and cash-on-cash return.

Real-World Scenario Example

"An investor buys a $300,000 rental property with 20% down at 7% interest over 30 years, renting it for $2,400/month with a 5% vacancy rate and typical operating expenses."

Inputs

purchasePrice:300000
downPaymentPercent:20
interestRate:7
loanTermYears:30
monthlyRent:2400
otherMonthlyIncome:0
vacancyRatePercent:5
propertyTaxAnnual:3600
insuranceAnnual:1500
maintenancePercent:5
managementPercent:8
hoaMonthly:0
otherMonthlyExpenses:0
closingCostsPercent:3

Result

The property generates roughly $11,800 in annual NOI for a cap rate near 3.9%, with a monthly cash flow of about -$112 after debt service, reflecting a modest negative cash-on-cash return at this price and rent level.

Important Disclaimer

This calculator provides estimates for educational and planning purposes only. Actual cap rates, cash flow, and returns depend on factors such as financing terms, local market conditions, property condition, and tax treatment. Consult a real estate professional, lender, or financial advisor before making investment decisions.