mortgage affordability calculator

Rental Property Cash Flow Calculator

Determine the potential profitability of your investment property by calculating net monthly and annual cash flow.

Monthly Income

Monthly Fixed Expenses

Variable Expense Estimates (%)

These percentages apply to Gross Rent.

Total Monthly Income: $0.00
Total Monthly Expenses: $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 pocket each month after all operating expenses and mortgage payments have been collected and paid. A positive cash flow means the property is generating income, while a negative cash flow means you are paying out of pocket to hold the investment.

Why Positive Cash Flow is Critical

While appreciation (the increase in property value over time) is a major benefit of real estate investing, it is "paper wealth" until you sell. Positive cash flow provides immediate benefits:

  • Risk Mitigation: Extra income helps absorb unexpected repairs or vacancies without personal financial strain.
  • Reinvestment: Excess cash can be used to pay down the principal faster, improve the property to increase rent, or save for a down payment on another investment.
  • Passive Income: Ultimately, the goal is to build a stream of income that requires little active effort to maintain.

The Cash Flow Formula

The basic formula used in our calculator is straightforward:

Gross Income – Total Expenses = Net Cash Flow

However, getting an accurate number requires accurately accounting for all expenses, including those that don't happen every single month.

1. Monthly Income

This is primarily the rent you collect. It may also include other income sources such as coin-operated laundry machines, paid parking spots, or vending machines on the premises.

2. Fixed Monthly Expenses

These are costs that remain relatively constant month-to-month:

  • Mortgage Payment (P&I): The principal and interest portion of your loan.
  • Property Taxes: The monthly portion of annual city or county taxes.
  • Insurance: Landlord insurance policies.
  • HOA Fees: If the property is part of a Homeowners Association.

3. Variable Expenses & Reserves

Many new investors fail because they ignore these "hidden" costs. Even if you don't pay them every month, you must account for them monthly to get a true picture of long-term cash flow.

  • Vacancy Rate: Properties will not be occupied 100% of the time. A standard estimate is 5% to 8% of gross rent, setting aside money for times between tenants.
  • Repairs & Maintenance: To handle routine fixes (leaky faucets, painting) and larger capital expenditures (new roof, HVAC). Setting aside 5% to 10% of rent is prudent.
  • Property Management: If you hire a professional manager, they typically charge between 7% and 10% of the collected rent.

Example Calculation

Let's assume you buy a single-family home. You rent it out for $1,600 per month. Your mortgage P&I is $900. Taxes and insurance combined are $200. You decide to manage it yourself but set aside reserves for vacancy and repairs.

  • Gross Income: $1,600
  • Fixed Expenses: $1,100 ($900 Mortgage + $200 Tax/Ins)
  • Vacancy Reserve (5%): $80
  • Maintenance Reserve (5%): $80
  • Total Monthly Expenses: $1,260
  • Monthly Cash Flow: $1,600 – $1,260 = $340

Using the calculator above will help you quickly analyze different scenarios to ensure you are making a sound investment decision.

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