Real Estate
Rental Cash Flow Calculator
Estimate effective monthly rental income, monthly net operating income, monthly cash flow after debt service, and annual cash flow from scheduled rent, other income, vacancy allowance, operating expenses, and mortgage payments.
Effective monthly income-
Monthly net operating income-
Monthly cash flow after debt-
Annual cash flow-
Exact scenario comparison
Vacancy allowance (%) scenarios
Exact scenario comparisonVacancy allowance (%) changes while all other entered assumptions remain constant.
| Vacancy allowance (%) | Effective monthly income | Monthly net operating income | Monthly cash flow after debt | Annual cash flow |
|---|
Period-by-period detail
Monthly schedule and annual summary
How to use Rental Cash Flow Calculator
- Enter scheduled rent and other recurring property income, then apply a vacancy allowance to the combined amount.
- Enter operating expenses before financing and monthly debt service separately so NOI and after-debt cash flow remain distinct.
- Review monthly and annual cash flow, then add capital expenditure, leasing, tax, reserve, and irregular repair assumptions outside this simplified model.
Calculator guide
Understanding Rental Cash Flow Calculator
Rental income is not the same as property cash flow. Scheduled rent must first be reduced for vacancy and operating expenses to produce net operating income, and only then should financing be deducted to show the cash remaining for the owner.
Calculation method
How the calculation works
Reduce scheduled income by vacancy, subtract operating expenses to obtain NOI, and then subtract debt service to estimate cash flow. Reduce scheduled income by vacancy, subtract operating expenses to obtain NOI, and then subtract debt service to estimate cash flow.
Worked situations
Practical examples
- Combine parking, laundry, storage, and other recurring property income in the other-income field only when collection is reasonably supportable.
- Enter management, repairs, insurance, taxes, utilities paid by the owner, and routine maintenance in monthly operating expenses.
- Keep mortgage principal and interest in debt service rather than operating expenses so NOI remains independent of financing.
Better inputs
Useful tips
- Base vacancy on local history and lease turnover rather than assuming every unit remains occupied all year.
- Create a separate reserve for roofs, systems, appliances, tenant improvements, and other irregular capital work.
- Compare actual monthly statements with the model and update rent, vacancy, expenses, and debt service separately.
Before relying on the result
Limitations and common mistakes
- The calculation uses one average month and does not model lease dates, seasonal vacancy, delinquency, concessions, or uneven repairs.
- Capital expenditures, leasing commissions, income taxes, depreciation, appreciation, sale proceeds, reserves, and financing changes are excluded.
- Property condition, legal compliance, tenant rights, insurance coverage, and marketability require local professional review.
Reference
Key terms
- Scheduled income
- Rent and other recurring income before vacancy or collection loss.
- Effective income
- Scheduled income after applying the entered vacancy allowance.
- Net operating income
- Effective income less operating expenses, before debt service and income tax.
- Cash flow after debt
- Net operating income less monthly mortgage or other property debt service.
Important note
Calculated from the entered property and financing assumptions. It does not replace lender, appraisal, legal, tax, or investment review.
Frequently asked questions
Should mortgage payments be included in operating expenses?
No. Deduct debt service after calculating NOI so property operations can be compared independently of financing.
Where should replacement reserves be entered?
Include a monthly reserve in operating expenses when the goal is conservative spendable cash flow, while labeling it separately in detailed underwriting.
Does vacancy apply to other income too?
This simplified page applies the entered vacancy percentage to rent and other income together.
Is positive cash flow the same as a good investment?
No. Initial cash, capital risk, appreciation, taxes, management burden, financing terms, and alternative returns also matter.