Rental Property (Cash Flow) Calculator
Estimate rental cash flow and NOI using vacancy, operating expenses, reserves, and financing. Great for quickly screening a deal before you build a full pro forma.
Inputs
Results
- Effective rent (after vacancy): $1,995
- Operating expenses (incl. PM): $860
- NOI: $1,135
- Mortgage: $1,279
- Cash flow: -$144
Tip: Add closing costs for a full pro forma. Use the projection below to see rent growth and appreciation over time.
Long-term projection
After 10 years: $174,147 equity, -$4,302 cumulative cash flow, property worth $335,979 with $161,832 left on the loan. Assumes 2% annual rent growth (expenses grow at the same rate) and 3% appreciation — projections are estimates, not guarantees.
When to Use This Calculator
Use this calculator when you're evaluating a potential rental property investment. It helps you determine if a property will generate positive cash flow after accounting for all real-world expenses including vacancy, maintenance reserves, and property management — the costs that sellers' pro formas often conveniently leave out.
How It Works
This calculator follows professional underwriting standards by separating income, operating expenses, and debt service. It calculates Net Operating Income (NOI) to evaluate the property's operating strength, then layers in financing to show actual monthly cash flow and cash-on-cash return. All default assumptions are intentionally conservative.
Key Terms
How to Use This Rental Property Calculator (Mini Guide)
This is a quick underwriting pass to estimate cash flow and NOI using vacancy, reserves, and operating expense assumptions — so you don’t buy “paper cash flow.”
What this calculator measures
It estimates: monthly cash flow, NOI (income after operating expenses), and simplified returns.
It’s meant to answer: “Does this deal survive real expenses and still cash flow?”
Inputs that matter most (verify these first)
Market rent (not seller rent): validate with comps.
Vacancy: even great rentals go vacant — 0% is unrealistic.
Taxes + insurance: often change after purchase and vary by location.
Reserves (maintenance/CapEx): prevents ‘cash flow’ disappearing after a roof/HVAC/turnover.
3-minute underwriting workflow
Enter purchase price + financing terms.
Enter market rent + realistic vacancy.
Enter taxes/insurance (or start with defaults, then refine).
Keep reserves non-zero unless you have strong documentation that it’s truly turnkey.
How to interpret the output
If cash flow is barely positive, one repair can flip the deal negative.
NOI helps compare deals across markets. Cash flow tells you if the deal pays you monthly after debt.
For accuracy, treat rehab, closing costs, and initial reserves as part of your cash invested.
Next steps
If it fails: don’t force it — price is likely too high or rent is overstated.
If it passes: stress test vacancy and expenses, then build a fuller 5–10 year model.
Try with Local Assumptions
Select a city to pre-fill the calculator with local market defaults.